Gemtech 3-Lug Mount, GM-9/MM9, 9MM, For HK MP5, Female Quick Disconnect, Black 12180 This mount screws into the rear of all GM-9" MULTIMOUNT and older TRINITY suppressors to allow use on the HK MP5 barrel with 3-Lug as well as other barrels modified with Gemtech's male 3-lug adapters.