The brand new, heavy duty 3-lug adapter is a quick-attach mounting option designed to provide added strength and longevity to your 3-lug equipped firearm.This fully enclosed assembly contains a mounting interface machined from 17-4 stainless steel-making it durable and capable of handling heavy use-including full auto.The hd 3-lug adapter is hub compatible and uses the iconic, hk tri-lug interface.This makes for a versatile adapter, capable replacing any 1-3/8"-24 mount.The hd 3-lug adapter can be swapped onto your r9 or nitro n20 sound suppressors, and can be used on some rifle calibers.This is the perfect upgrade if you are looking for a quick-attach mount with better longevity-especially on full auto platforms.Replaces any 1-3/8"-24 mount.Aluminum and stainless steel construction.Matte black finishModel: 3-Lug