Brownells - Magpul XTM Hand Stop
Hand stops of various types have become popular as foreign grips on rifles and carbines and for very good reasons.
WARNING: Never attempt to disassemble or reassemble a firearm unless you are absolutely certain that it is empty and unloaded. Visually inspect the chamber, the magazine and firing mechanism to be absolutely certain that no ammunition remains in the firearm. Disassembly and reassembly should follow the manufacturer’s instructions.