Can position just enough rail area exactly where you need it for each accessory, available in six lengths. 13 Slots 0.65Oz, 11 Slots 0.56Oz, 9 Slots 0.48Oz, 7 Slots 0.36Oz, 5 Slots 0.28Oz, 3 Slots 0.19Oz, much lighter than aluminum alloy, high strength and good safety.