TACFUN FSI Tactical Micro Green + Red Dot Reflex Sight Compact 1x20 Dual Illuminated 20mm Picatinny/Weaver Mount Aircraft grade alumium to withstand constant heavy recoil Nitrogen charged with weather resistant sealsFog proof and shock-resistant housing Coated lens provides superior light transmission, resolution and scratch resistanceUnlimited eye relief for quick target acquisition Dual-illuminated (Red, Green) 4 MOA dot reticle with adjustable rheostat for brightness control, Integrated Weaver / Picatinny 1913 mounting system 2,000 hours of battery life on low setting. Includes protective lens cover