Arisaka Defense Rail Slider, Picatinny Rail M-Lok, 6 Slot, Fits M-LOK, Integrated QD Mount, Anodized Finish, Black RS-RAIL-6M Make Picatinny Great Again with Arisaka's precision machined 1913 Picatinny Rails" designed specifically to be used with the Arisaka Rail Slider. These rails feature an anti-rotation QD socket at one end" and include standard and short screws to help alleviate any clearance issues around gas blocks or thicker barrel contours. Please note: The lengths are based on how many full M-Lok slots the rails cover. For example" the current Knights Armament SR25 CC would use the 8 M-Lok slot rail to cover the entire 6 o'clock position on the handguard.