Cross Armory's Flop Stop holds the upper receiver of your AR-15 in the open position for faster, safer, and more convenient reloads where compliance requires separating the upper receiver from the lower receiver. When the receivers are opened, the weight of the barrel causes the upper receiver to fall forward, pinching fingers and creating an unstable and dangerous weapon. The Flop Stop protects both you and your weapon. This model includes Cross Armory's Pin Pal front takedown pin replacement with a locking nut and lubricated captive bearing to help prevent undue wear on the front pivot point. The Pin Pal is made from 4140 ordnance steel with melonite hard coat, and is removable should you choose to return to your factory configuration. The Flop Stop is designed to work with all other compliance products, not limited to Cross Armory and the Pin Pal fits any standard AR-15 configuration.