This direct replacement hop up inner barrel clamp is a reinforced nylon polymer segment that is integral to the LM4 Series hop up. It appears as part 5 on any LM4 diagram, but is also part 5 on the PTS MKM AR-15 and PTS MML MATEN. Most internals for the PTS MKM AR-15s are compatible with the LM4 PTR Series.
