Samson's KeyMod rail section allows you to customize your KeyMod handguard to accept any accessory that mounts to the M1913 Picatinny rail system. The beauty of the KeyMod system is it's adaptability...you aren't stuck with full length rails at the 12, 3, 6, and 9 o'clock positions. This rail kit includes everything you need to mount that light, laser, or whatever at the position YOU want it. Two inch rails come in package of 2, all others include only one rail section.