Tritium is a form of hydrogen used as a self-powered light source, eliminating the need for batteries or electricity. Troy Industries’ Tritium Battlesights support the shooter’s eyesight in minimal light situations. Just because the light’s not perfect doesn’t mean your shot shouldn’t be. The Troy Industries Gas Block Mounted Front Sight. It’s been a long wait, but Troy has engineered a rugged, reliable, combat ready BattleSight that mounts securely on the gas block. It offers all of the features of Troy’s other Folding BattleSights: Easy to operate, clicks solidly into place and folds out of the way when not needed. (Not compatible with four-sided rail gas blocks). Made in the U.S.A. - Mounts securely on the gas block. Offers all of the features of Troy’s other Folding BattleSights. - Built-in swivel attachment on both sides - Flat Dark Earth