Weaver's Locking Rail Panels protect unused rail areas from damage while providing a gripping surface that shields the operator from weapon heat and sharp rail edges. Made of a tough, ridged polymer and using the patented Rail-Lok integral locking mechanism to keep themsecurely in place, these low profile rail panels improve feel and weapon control. Sold in sets of two, these panels are perfect for use on those small uncovered rail areas next to mounted accessories. Medium version is perfect for full coverage of SCAR 3 and 9 o'clock rails.