Review on Feyachi Red/Green Laser Sight Low-Profile Compact Picatinny Rail Laser For Pistol Handgun Shotgun Rifle by William Hood

Not mentioned in instructions: when installing the two button batteries, note that one goes up and the other goes down. Polarity direction is noted on the circuit board. Instructions illustration does not show this. First time I tried to install the batteries, I thought that they were dead on arrival (not uncommon with batteries shipped with products). Battery meter showed that they were good, not dead. Also, inserting the batteries is frustrating because the fit is tight, and the compartment lid does not swing very far up.