No connection with the seller, but this is a meter much like one I have. The three button cells MS-76 are readily available and proper for the meter.
The characteristic of this meter is that the needle snaps immediately to a reading. This makes it a very satisfying experience to use it. I had a Soligor analog meter where the needle jumped around because the trigger button was a metal sliding contact. The Pentax has a microswitch type switch I think, that just "clicks"