Troy Industries BattleSight Folding Front M4 Sight. Fits on any RIS top rail system. Durability and dead-on accuracy have made Troy Industries Folding BattleSights the hands-down choice of Special Ops and tactical users worldwide. Easy to install and to deploy, with no levers or springs to fumble with, these sights position apertures at exact factory height. A stainless-steel cross-locking system ensures sights remain upright and zeroed under extreme combat conditions. A push of a button folds the sights securely out of the way until you need them again (they fold to a profile of just 0.460). Troy BattleSights feature a zero-canting attachment system for use on all military and aftermarket receivers.