Upgrade your AR with our lo-profile gas block. Designed to fit barrels with a .936 diameter, this high-quality piece helps to improve the performance of your firearm. Its made from durable materials and easy to install, making it a must-have for any AR owner. Plus, its low-profile design wont add unnecessary weight or bulk to your rifle. Two 8-32 Set Screws (requires a 3/32 Allen wrench), .340 from Center to Center of Holes, 1 Roll Pin