The CGS Group Three Lug Mount is designed for use with HK type three lug adapters. It features an encapsulated assembly and an exterior 1" hex feature. This feature allows the user to get a wrench on the three lug mount for installation and removal from the silencer, as well as to use the mount as a tool for your three lug adapter if required.
The CGS three lug mount has a unique machining operation done to the lug seats which ensure that all the lug seating surfaces are on the exact same plane, something you won't find on any other three lug mounts. An issue with traditional three lug mounts is that on occasion the end mill will slip into or out of its collet and cut the lug seat either too deep or too shallow creating an uneven seating plane for the three lug adapter to shoulder on, leading to a lack of perpendicularity to the bore which can lead to baffle and endcap strikes. Made in the USA by CGS, the three lug mount machining process ensures the lugs are all on the same plane and this allows the mount to be perfectly perpendicular to the bore
picture credit: Chaos Group, Inc. and unknown