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. Available soon – email or call for information. - Mounts securely on the gas block. Offers all of the features of Troy’s other Folding BattleSights. - Built-in swivel attachment on both sides - Black