This extra long extension can be used to add length to your barrel without changing the threads. Can be used to add length to a barrel to extend out from a hand guard and use the same suppressor or muzzle brake/comp. Made of 4140 steel and finished in durable black oxide. Thread in 1/2x28 on one end and 1/2x28 of the other end. Total length is about 2", subtract each thread, (.50" each), overall thickness is .74" OD.