I have one of those wristwatches that doubles as an FRS radio...

The battery is a 3.7V 540mAh, it's about 3/16" thick, 1 7/8" long and 1 1/4" wide.

looks like these:
http://malintech.en.alibaba.com/prod...ml?showimg=yes

You know what I'm thinking.

Plus, I don't need to buy or build a charger. just put it back in my watch and plug the watch into it's charger.

Audiovox wants $22 plus about $7 shipping and handling, but I bought my FRS Watch for $19.99... so the heck with that. Go to the FRS radio aisle at walmart and you'll see lots of little FRS radios with these batteries.