The Troy HK Front Folding BattleSight is easy to install and to deploy, with no levers or springs to fumble with, and position apertures at exact factory height. A stainless-steel cross-locking system ensures sights remain upright and zeroed under extreme combat conditions. With the push of a button, sights fold 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. No tools required for adjustment. Each click adjusts .50 MOA. Sight can be moved or taken off without permanent modification to the firearm.