Using the Aimpoint Micro H - 2 AR15 is easy. First, install the sight on your AR15 using the included Micro™ LRP Mount and 39 mm Spacer. Insert the CR2032 Battery. You can adjust the dot intensity with the 12 settings to suit different lighting conditions. When not in use, put on the flip - up lens covers to protect the lenses. Keep in mind that although it's submersible up to 5 meters, don't leave it underwater for too long. For maintenance, clean the lenses gently with a soft cloth. Replace the battery when the sight starts to dim. Enjoy using your high - quality Aimpoint sight!