Field Sport 3 Rails KeyMod Picatinny Accessory Rail Set, 5.7" With 11 Slots, 4" With 7 Slots and 3.35" With 5 Slots Field Sport 3 Rails KeyMod Picatinny Accessory Rail Set, 5.7" With 11 Slots, 4" With 7 Slots and 3.35" With 5 Slots