Durable full metal one piece construction Compatible with the F6613 M4 airsoft outer barrel Excellent as a sturdy replacement for a damaged flip up sight Assists in accurate shots when firing at targets close to mid-rage Provides a front sight without having to occupy rail optic rail space In the Box 1X Flip Up Sight Specifications: Brand Golden Eagle Build Metal Compatibility Picatinny Rails Color BLACK California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov