And it has hard reciprocating motion same as Piston

CNC machined stainless steel shaft

Padded H-harness with Hook & Loop

and it is not easy to generate high temperature due to friction to cause HOP skin to expand

the pack is lightweight

MAGPUL M-LOK HAND STOP KIT Color:Grey And it has hard reciprocatingThe M LOK Hand Stop Kit serves as a light weight, low profile M LOK slot index point for improved weapon control, or as a forward stop to prevent the shooter's hand from reaching the hot front sight assembly or muzzle. The kit includes one M LOK Hand Stop, one M LOK Index Panel, and one M LOK Rail Cover Type 2 for the individual user to configure their kit as they desire. Also included in this kit is an adapter for use with Magpul M LOK equipped