Save some dough and rehab your dead IF Batteries!
The cell used is an Energizer 2L76, I was able to find it at my local hardware store for around $5
Carefully make a pass around the seam with a razor blade or utility knife to brake through the bit of glue holding the ring on:
Continue by gently prying off the ring:
Once apart you’ll be looking at four parts – housing, clip, battery and ring:
Replace the battery paying attention the ‘+’ sign is visible in the open end of the housing:
Put the ring back in place and the unit is ready to go back into the collar: