At GrovTec, they are extremely proud to produce rugged and reliable firearms accessories for everyone. Whether you're a hunter, an American service member, or a shooting sports competitor, they believe you deserve tools made by fellow Americans who share common ideals and pride in performance. The HUB Direct Thread Suppressor Adaptor - HYBRID UNIVERSAL BASE (HUB)- Mounts Suppressors Directly to Threaded Barrels - 1.375 X 24 HUB Mount Standard - Low Profile Flush Mounting.