Our Linear Inertial Decoupler (LID) device is intended for use with the GM-9 and MULTIMOUNT suppressor. It is required for all handguns that utilize the Browning-type action (Glock, Sig, HK, etc.) The use of the LID allows the pistol to properly cycle when the weight of the suppressor is added to the end of the barrel. RSR - MPIMAG598GRY