Cross Armory's Quick Pins are easier to operate than standard rear takedown pins, providing a one-pinch upper and lower receiver release system. This device allows fast, reliable access to the most important parts of your weapon enabling you to service or fix mechanical failures at the range then get back on target quickly and safely. Open with a simple pinch of your finger and automatically lock back into place simply by closing. Compatible with Mil-Spec AR-15/M4 firearms.