The Mepro GLS, 40 mm grenade launcher sight system provides the user with an accurate optic from 50-400m. (54-420 yd). Historically, experience has shown with grenade sight optics that accuracy is problematic at best. Compounding the issue, their use was pretty much limited to daylight hours. Meprolight, utilizing state-of-the-art design and manufacturing equipment, built a dual illuminated optical grenade launcher reflex sight that functions day or night in all weather conditions. The dual self-illuminated internal power system will operate continuously for years without batteries or an external power source. The highly durable, MIL-SPEC, MEPRO GLS features large eye relief, Mfg: Meprolight