*The M37 loupe adds variable 1.5X to 5X magnification to the V30 red dot sight and maintains a wide field of view with a comfortable 2.2-3.6 inch eye relief.*V30 red dot sight equipped with auto on/off function. It turns on when it detects movement and automatically turns off when it detects no movement in 1 hour.*With multi-coated lenses that provide a clean, bright point of view without darkening. Crisp 2MOA red dot for precise aiming with both eyes open. Unlimited eye relief for rapid target acquisition.Feyachi V30 2MOA Red Dot Sight with M37 1.5X - 5X Magnifier Combo, Absolute Co-Witness