The Valken RDA30 Red Dot Sight is a low profile airsoft optic with a 30mm tube diameter. The RDA30 has a strong and lightweight nylon fiber reinforced housing, and mounts to most 20mm picatinny and weaver rails. This airsoft red dot includes a CR1620 battery to illuminate the bright CQB reticle with 5 brightness settings. The red dot offers a phase coated lens for a clear image with true color, and an additional 20mm accessory top rail for mounting additional accessories. The turret click value is 3 MOA field of view at 100 yards, and they make a great first airsoft optic.