Upgrade your AR with the lo-profile gas block. Designed to fit barrels with a .750 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. 2 Set Screws (requires a 3/32 Allen wrench), 1 Roll Pin, 10-321/4 socket screw cone point alloy in black