http://www.insurgenttactical.com/http-www-insurgenttactical-com-product-p-thr15-h-p/thr15.htm

Insurgent Tactical's slim, free-float rail machined from 6061-T6 billet aluminum with a Mil-Spec Type III hard coat anodizing finish. Full length 12 o'clock Picatinny rail with machined Picatinny rails at the 3-6-9 o'clock positions on the front of the handguard. T-marks are provided on all rail sections. Designed with both anti-slip and anti-rotation features. Magpul M-Lok attachment system throughout the rail for multiple mounting options of accessories. Ambidextrous quick detach sockets providing 2x QD locations on each side of the handguard. Barrel nut requires 1 1/8" crow's foot wrench for proper installation (not included).

LENGTH: 15"
MATERIAL: 6061-T6 Aluminum
WEIGHT (w/o hardware): 12.1 oz
WEIGHT (w/ hardware): 14.0 oz
INTERIOR DIMENSIONS: 1.375"
OUTER DIMENSIONS (w/o Picatinny quad rail section): 1.529"
OUTER DIMENSIONS (with Picatinny quad rail section): 2.315"
BARREL NUT: 7075-T6 Aluminum
MADE IN USA