Holosun 515GM 1x 20mm Red Dot - 2 MOA Dot with65 MOA Circle - The HS515GM is a 20mm micro optical sight designed for rifle and carbine applications. Features include 7075 Aluminum Housing, Shake Awake, 12 brightness settings, Holosun's Green Super LED with up to 50k hours battery life, Multi-Reticle System, QD mount, Kill flash, and Clear Lens Caps. Quick Release & Detachable Mount T10 L Key User Manual CR2032 Battery Lens Cloth