Things You'll Need
Instructions
Unscrew the cap on top of the brightness adjustment dial (located on top of the scope). If necessary, place a coin in the slot on the cap and turn counterclockwise.
Remove the old battery (if installed) and replace with a new CR2032 3-volt lithium battery. The positive side (the flat side with lettering and the + symbol) of the battery must be facing upward.
Screw the cap back on.
Check the battery by turning the brightness adjustment dial to any setting and look through the scope. If the battery is operating, the red dots will be visible.
Return the brightness adjustment dial back to zero (the unit's off position) when not in use. Not doing so will drain the battery.