I have a laserlyte SCV3 which is 5 mW red laser - LaserLyte ? Sight SCV3
It is 3/4" long and runs on 4 of "377" type batteries, which are 6.8mm diameter watch batteries (different companies have different names for the type, including LR626, SR626, 1176SO, SR66, AG4, 376, and 377. Most don't...