The Valken RDA05 Reflex Red Dot Sight is a low profile airsoft optic with a 25mm lens. The RDA05 has a strong and lightweight nylon fiber reinforced housing, and mounts to most 20mm picatinny and weaver rails. This airsoft red dot includes a CR2032 battery to illuminate the bright reticle with 8 brightness settings. The red dot offers a phase coated lens for a clear image with true color, and the turret click value is 3.5 MOA field of view at 100 yards. They make a great first airsoft optic. We recommend our Valken Sight Protector Kit to help protect this red dot sight.