For those who purchase authentic arcade game motherboards, finding backup battery hardware isn't always a simple affair. ID'ing the battery, much less locating it can be a challenge.
For those who own a Capcom CP System II (CPS2) game motherboard, you'll want to purchase this model battery to replace your old one.
XENO XL-050FAX 3.6V LITHIUM BATTERY LS14250 1/2AA AXIAL LEAD
You can find this at www.bestbyte.net
Thanks to SRK's DEZALB for the suggestion.