Good Morning All, have a slight problem usually with old age and memory failure. I need to know what the part is on the attached picture. my memory has failed me i'm afraid. it's part of the power supply on a intrinsically safe circuit, I believe it's some sort of galvanic isolator fuse that doesn't cause an explosion if it pops. the manufacturers name on the side of it is Siemens and there is a number after which is 90 96 and what looks like either a 0 or and O. thanks in advance.

 

It looks like a gas arc discharge protection device to me. Like put across data lines to protect from close lightning strikes.

 

It looks like a gas arc discharge protection device to me. Like put across data lines to protect from close lightning strikes.

Yep that's the one, seriously old age is a bitch and my memory really is getting bad for remembering things. thanks for your help, off to farnell.

 

Gas discharge surge arrestor.

Markings VV YY O
VV = nominal voltage
YY = year of production
O = non-radioactive

https://uk.farnell.com/epcos/b88069x1380s102/gas-discharge-tube-90v/dp/564060?st=surge arrestor