Rail covers are made from a durable, heat & chemical resistant heavy-duty synthetic polymer resin material. Features include: compatible with all 1913 Picatinny rail systems, a robust retaining clip, pops up by hand for easy installation, adjustment and removal; positively locks down, reduces heat transfer and abrasions to the operators hand and, weights is 1oz each. Approximate length is 6". Sold in a 3-pack in black. Fits the SR-556®, SR-22®, and AR style of rifle with Picatinny rails on it. Made in the USA by Troy Industries.