Features: Extremely rugged one piece free float design and construction Featuring seven sides of M-LOK compatible slots Inside diameter 1.670 inch outside diameter 2.0 inch 1.95 inch over mounting flats Made for use with suppressors no larger than 1.55" in diameter High quality MIL-STD 1913 top rail T-marked for accessory location One five slot M-LOK polymer rail section included Barrel nut and barrel nut wrench included Construction from 6061 aluminum hard coat anodized for a lifetime of service 9.25" - 10.2oz MI Lifetime Warranty 100% Made in America - Keeps America Working US Patent Number USD788871