Designed to be used with a free floating handguard, this version of the Windham Weaponry Gas Block has a stud and sling swivel attachment machined in to accommodate QD Sling Swivels – a standard QD Sling swivel is included in this kit. It fits 3/4″ diameter barrels by slipping on and tightening with the supplied set screws. It’s Mil Std 1913 Rail will accommodate any aftermarket front sight. It has a pre-drilled gas path hole, gas tube hole and gas tube spring pin hole, and includes the Windham Weaponry “WW” machined into the front face. This rugged sight base is machined from solid billet, bead blasted, and then black manganese phosphated for a durable non-reflective surface. Made in the USA.