The VARTA 3/V150H/2P with Polarised Pins is one of the more popular in the Mempac range. Used in many memory back up applications, particularly for Central Heating Timers, like the Potterton.
Many of you will note that the original battery it now replaces was in a Blue Case, it was NiCd and known as 3V100R. Others with a Honeywell Timer will note that their outer case was Beige and has a small locating peg.
We do a version without pins which is the 3/V150H.