The new Switch MOD 2 Series takes the very best from the Switch Series and custom tailors it to fit the needs of our shooters. We eliminated the 12 O'clock picatinny section and replaced it with open vents. This gives a more streamlined appearance to the rail "but more importantly" allows the shooter to utilize the smaller diameter of the rail to manipulate the weapon more effectively. The vents allow better airflow from the barrel and helps eliminate heat build-up and allows the end user to run longer and cooler with this setup. Rest assured we still left a small section for back up iron sights. We also added M-LOK sections up front that gives you flexibility and freedom to run your light solutions. No more need for purchasing additional off-set light mounts. Mount it directly on the rail and go.Features:Black finish15.3 inches MOD2 M-LOK rail system1.34 inches internal diameterSpanner wrench needed to torque barrel nut to spec (not included)