I just picked up some NOS DIP reed relays which I plan to use on a project to create a relay array to replace an obsolete 6P3T mechanical switch on an old portable radio. The relays in question shows part no: PRME15005AB, GI Clare belgium 46-85. I found a datasheet online for a PRM15005AB by Cotorelay which I presume is a different manufacturer but same replacement part. Anyhow, I discovered that the AB suffix suggests this relay has diode and E.S. (shield) option. Can someone shed some light regarding how to use this E.S. shield option? Datasheet merely shows: Options: A = ES option - pin #9 B = Diode option - pin #13 is positive. AB = Shield and diode option. Option B is pretty explanatory. But how is pin #9 used? Tie to ground? Or just ignore? Thanks in advance.