♦ Extremely easy installation, all hardware and barrel nut is included♦ 1.750 inch inside diameter♦ High quality MIL-STD 1913 top rail♦ Magpul® M-LOK™ compatible for maximum accessory versatility♦ One five slot Magpul® M-LOK™ polymer rail section included♦ US Patent Number 9,453,694♦ Construction from 6061 aluminum, hard coat anodized for a lifetime of service♦ Fully dehorned for a non-abrasive, comfortable feel♦ MI Lifetime Warranty♦ 100% Made in America - Keeps America Working♦ US Patent Number USD788871Magpul® and M-LOK™ are trademarks of Magpul Industries Corp