Yankee Hill Machine Company AR-15/M16 Clamp-On Front Sight Gas Block
This video displays the various models of the rugged YHMC clamp-on front sight gas blocks.
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.