This versatile Triple Rail Mounting system has a single 3" Picatinny rail and two 2.5", 45-degree Picatinny rails. The rails can be used together or independently of each other. Use all three rails on lower handguards for grip with easy thumb access to light and laser on side rails or use 3" rail on bottom and the 2.5" rails on top. The 45-degree rails will not interfere with iron sights. The rails mount on the upper and lower vent holes of most existing standard handguards. Constructed of high-density polymer, the Triple Rail System fits M16/AR15/M4.