I just purchased the Klein digital multi-meter MM420 at amazon. There are a few questions I have that hopefully some may have the answers to. I called Klein regarding my inquiry to the MM420 and had to submit the details to techanical support. Their email stated:

Hello, Thank you for contacting Klein Tools. If your message requires a response, we will do our best to respond within 2 business days.

Thanks - Klein Tools Team

That type of response is enough not to purchase Klein ever again: "If your message requires a response".
My questions are:
1.) Why are there two 'Different' Revisional codes on the back of the packaging?
A.) On packaging at Bottom: 1380260 Rev. 03/22 B
B.) On packaging below Bar Code and Klein Tools, INC: 1330937 Rev. 04/25 E
* See Red Arrows denoting Rev. codes.
2.) Where is the Klein MM420 made? Many show and/or state China, yet on the Klein MM420 I purchased from Amazon, the meter states Made in Vietnam.
All replies are appreciated

 

1.) Why are there two 'Different' Revisional codes on the back of the packaging?

My opinion: Those codes refer to the text and layout of that piece of packaging and have nothing to do with the device actually inside the package.

That type of response is enough not to purchase Klein ever again: "If your message requires a response".

What's wrong with that? I'm sure they get plenty of communications that don't require feedback. They're just trying to be precise and cover all cases with one sentence.

 

My opinion: Those codes refer to the text and layout of that piece of packaging and have nothing to do with the device actually inside the package.

What's wrong with that? I'm sure they get plenty of communications that don't require feedback. They're just trying to be precise and cover all cases with one sentence.

*Wrong.
READ HERE:
Based on common manufacturing practices and Klein Tools' product updates, the presence of two different Revision (Rev) codes on a new Klein MM420 multimeter—typically found on the back of the unit or the packaging—usually indicates a distinction between the design/hardware revision and the production/firmware revision.
Here are the most likely reasons for two different Rev codes:
Hardware vs. Component Update: Manufacturers often update internal components (like a new chip, display supplier, or PCB revision) while keeping the overall design the same. The "Rev A" might indicate the initial housing mold, while a "Rev 02" on the PCB indicates a later component update.
Running Change/Product Refreshes: Klein has refreshed their test and measurement line to improve features, such as enhancing accuracy or adding safety features. A new meter might have an original base model revision (e.g., A) with a newer production run revision (e.g., B) indicating it was made after a running, non-advertised change.
Production Date Codes: One revision code often refers to the PCB revision, while the other refers to the production batch or final assembly revision.
Important Information regarding MM420 Versions:
Klein refreshed their meter lineup recently to include improved accuracy (TRMS) and features like Lead Alert (green LEDs for probe placement). It is common for these updated units to have multiple identifiers to differentiate them from older, non-TRMS or earlier-generation models, ensuring they are recognized as the 600V CAT III rated devices.
Conclusion:
You likely have a unit that combines a base design revision with a later production or firmware revision, which is standard in electronic manufacturing. As long as it is an authentic Klein product, both revisions are meant to work together seamlessly.

 

My opinion:

What's wrong with that? I'm sure they get plenty of communications that don't require feedback. They're just trying to be precise and cover all cases with one sentence.

** The fact is that the reply from Klein was substandard and sarcastic. And, the question I posed has significant relevance to any hardware updates, firmware revisions, that are crucial factors as noted in my previous response.

 

** The fact is that the reply from Klein was substandard and sarcastic.

Your opinion only.

And, the question I posed has significant relevance to any hardware updates, firmware revisions, that are crucial factors as noted in my previous response.

Well fine but that was an automated response sent by their server to acknowledge that your inquiry has entered the queue. It was not a human judgement.

 

Your opinion only.
Well fine but that was an automated response sent by their server to acknowledge that your inquiry has entered the queue. It was not a human judgement.

One and done with Klein. Many corporations are following suit in that 'no reply' is allowed and no personal communication with technical support. This is due to the fact that Klein or any other manufacturer does not wish to be bothered. This type of business management is becoming more prevalent. If you have not noticed this directional change, you do not conduct business online.* And, you never addressed country origin (Where made). Thank you very much for the courtesy.

 

And, you never addressed country origin (Where made).

I have no knowledge of the facts regarding origin. Better to keep quiet.

 

** The fact is that the reply from Klein was substandard and sarcastic. And, the question I posed has significant relevance to any hardware updates, firmware revisions, that are crucial factors as noted in my previous response.

So, when your message to them ended with, "All replies are appreciated", that was obviously not the case, as you clearly didn't appreciated an automated response whose only purpose was to let you know that your message was received and giving an idea of the time frame you could expect a response if your message was one that required a response.

They get lots of messages that don't require a response. For instance, a message along the lines of, "I've found your meter to be a solid unit for the price point."

One and done with Klein. Many corporations are following suit in that 'no reply' is allowed and no personal communication with technical support. This is due to the fact that Klein or any other manufacturer does not wish to be bothered. This type of business management is becoming more prevalent. If you have not noticed this directional change, you do not conduct business online.* And, you never addressed country origin (Where made). Thank you verty much for the courtesy.

How do you expect strangers on the Internet to know which production facility your particular meter came off of? Many consumer goods, particularly electronics, have production lines located in many different locations, so the fact that "many" show or state China does not mean that ALL units are made in China. Your unit explicitly states that it was Made in Vietnam. Chances are, it was made in Vietnam. Now, what does it mean to be "made" anywhere? It's highly likely that many of the components that went into it were sourced from facilities in several different countries. There are different thresholds that can apply to determine where the product will be considered to have been "made". Generally, the point of final assembly, testing, and packaging determine country of manufacture. So large companies play games in order to move just enough of that final bit to a country with favorable tariff and/or trade agreements with their various markets to be able to claim manufacture there. So, it's possible that your unit was almost completely manufactured in China (or someplace else) and then shipped to Vietnam, where they snapped the PCB into a case, snapped the case together, did a functional check, and then put in into the package, which may have come to them with the unit already printed, molded, and ready to go.

 

So, when your message to them ended with, "All replies are appreciated", that was obviously not the case, as you clearly didn't appreciated an automated response whose only purpose was to let you know that your message was received and giving an idea of the time frame you could expect a response if your message was one that required a response.

They get lots of messages that don't require a response. For instance, a message along the lines of, "I've found your meter to be a solid unit for the price point."

*** As a ponit of interest to your message> "There are 10 types of people in the world: those who understand binary, those who don't, and those who can work in any number base". 'I hate "Binary" maybe more so than AI'! "I left the electronics arena when digital allegely overcame analog. *However, "Guess what" 'The Chinese are using analog in their military systems". Can you believe it? I'm still old school.



How do you expect strangers on the Internet to know which production facility your particular meter came off of? Many consumer goods, particularly electronics, have production lines located in many different locations, so the fact that "many" show or state China does not mean that ALL units are made in China. Your unit explicitly states that it was Made in Vietnam. Chances are, it was made in Vietnam. Now, what does it mean to be "made" anywhere? It's highly likely that many of the components that went into it were sourced from facilities in several different countries. There are different thresholds that can apply to determine where the product will be considered to have been "made". Generally, the point of final assembly, testing, and packaging determine country of manufacture. So large companies play games in order to move just enough of that final bit to a country with favorable tariff and/or trade agreements with their various markets to be able to claim manufacture there. So, it's possible that your unit was almost completely manufactured in China (or someplace else) and then shipped to Vietnam, where they snapped the PCB into a case, snapped the case together, did a functional check, and then put in into the package, which may have come to them with the unit already printed, molded, and ready to go.

** Well I'm still miffed as I received a call from Klein Tools by David, actually shocked. This has changed my view somewhat. David told me via phone that the manufacturing has moved to Vietnam , most likely being last year (2025). In that respect, no parts are subbed out to China and/or assembled in China. In fact, I made mention of the tariffs as being far below in Vietnam as opposed to China whereby more revenue can be accrued by Klein (Profit) : 'Common sense'. * You're going out on a limb claiming that China or another country manufactured the parts, snapping the PCB's into a case, then shipping to Vietnam. To me that would highly be unlikely as Vietnam also delves into transistors, capicitors, and resistors that would be used in raceway circuitry in PCB's. Am I correct?, "Who knows". Again, the probability of China performing the bench work then shipping to Vietnam would be construed as 'unlikely' unless there is some critical agreement in that China has with Vietnam. By no means are you a slouch in this area. I very much appreciate the professional support.

 

** Well I'm still miffed as I received a call from Klein Tools by David, actually shocked. This has changed my view somewhat. David told me via phone that the manufacturing has moved to Vietnam , most likely being last year (2025). In that respect, no parts are subbed out to China and/or assembled in China. In fact, I made mention of the tariffs as being far below in Vietnam as opposed to China whereby more revenue can be accrued by Klein (Profit) : 'Common sense'. * You're going out on a limb claiming that China or another country manufactured the parts, snapping the PCB's into a case, then shipping to Vietnam. To me that would highly be unlikely as Vietnam also delves into transistors, capicitors, and resistors that would be used in raceway circuitry in PCB's. Am I correct?, "Who knows". Again, the probability of China performing the bench work then shipping to Vietnam would be construed as 'unlikely' unless there is some critical agreement in that China has with Vietnam. By no means are you a slouch in this area. I very much appreciate the professional support.

I never made any claim about how your meter, or Klein in general, manufactures their products. I provided a generic description of how many companies operate. I have no idea what Klein's production stream is like. The only things I said specific to your meter was that the package says that it was made in Vietnam and that, most likely, meant that it was made in Vietnam, for whatever definition of "made in" applies.

Why are you still miffed? Not only did they respond to your message, they did it with a phone call! Just what are you expecting?

 

Hi Synop12,
Does the Klein digital multi-meter MM420 you bought from Amazon, perform as per the Amazon advertised specification, or not?

E

 

** The fact is that the reply from Klein was substandard and sarcastic.

The fact is - it wasn't, but you chose to view it in that way. An automated reply acknowledging receipt and later attention by a human is a standard way of processing such interactions. I'd suggest you try and read it less personally.

Seems that Klein have proved to be responsive and helpful - kudos to them, I think.

 

Hello. Welcome to AAC.

Please take the following in the spirit in which it is meant: friendly, helpful, and non-judgmental.

First, you seem a bit agitated by this. From outside, that agitation appears to be out of scale with your situation. Maybe the cost of the meter represents a large investment for you(?). In any case, taking a step back and trying to evaluate your response with an eye to debunking your own impressions might help to give you some peace of mind.

Here's some information that might possibly help:

The Revision Numbers
As was suggested earlier in the thread, the numbers on the packaging are document revision control numbers entirely unrelated to the product enclosed except for the correlation of the features listed on the two inserts. Your "evidence" was just an AI attempt to be "helpful". Always insist on alternative explanations when using LLM AI to research, and propose—neutrally—any alternate explanations you are given (e.g.: Are the numbers document revision control numbers?) and see if the bot backtracks—which it often will.

The clear evidence for document revision and not PCB/firmware silliness is found on the many other Klein products that come in clamshell packaging, for example, this step bit:

​

Here is a product with no PCB and no firmware—but it does have a package insert, that that insert has numbering in the same format as the electronic device. The AI explanation was, it turns out, an elaborately crafted plausible but completely invented answer.

Country of Origin
Lately there is a trend of companies moving their manufacturing from China for several reasons. These include labor costs, tariffs, politics, IP rights, and others. Vietnam has developed (along with the more longstanding Malaysia) as a good choice for companies selling electronic devices because of the post-COVID rejiggering of supply chains, the increasing knowledge about electronics manufacturing in the work force and the presence of major players in the country—including Apple and Samsung.

Klein's move to Vietnam makes perfect sense because it allows them to maintain the existing retail price while also maintaining their margin. If they were raising prices in response to the tariffs on China and moving to Vietnam to avoid them, your gouging accusation might make sense—but that's not what is happening. Klein is already priced as a premium product, if they raised the retail price they would lose sales.

Customer Service
Klein's customer service is known to be very good. A 48 hour turnaround on support requests represents a reasonable staffing for a company that does as much volume with as large a product line as they do. Despite your read of their automated message as "substandard" I fail to see anything negative enough about it to comment on. Concerning "sarcastic", that idea is just—strange.

Why would a company taunt customers looking for support? Who in their right mind at a corporation the size and age of Klein would approve such a thing? What would the benefit to them be?

The reply might have been impersonal, but there is no sarcasm in it at all. Klein manufactures some excellent products, and their meters have been generally reviewed as very good value for the money. Avoiding their products based in this experience would be a loss for you, not just them.

Please consider taking a step back, a deep breath, and enjoy your new meter—it should give many years of good service.