The Low Profile Rail Adapter Kit will work with most rail types such as Ops-Core ARC rails or M-LOK type rails. They allow the user to seamlessly integrate hearing protection headsets or communications systems (headset guide) directly onto helmet rails. This eliminates the need for an uncomfortable strap underneath the helmet that eventually creates hotspots and headaches. *Important* When mounting to M-LOK, ensure the T-Nut is vertical in the slot. If it's angled there will not be enough material for the nut to hold onto causing them to pop off under strong pressure! Also ensure not to over torque the bolt and to use the included Loctite!   Our goal when designing the low profile rail adapter kit was to create a headset adapter that minimized the overall profile of the entire tactical helmet headset system. This required the use of lightweight aluminum and glass filled nylon parts to get the strength, durability, and rotation we needed from the adapters. The end result is a ballistic helmet adapter that is 80% slimmer than the next competitor. We have recently updated the as well to feature built in wire springs to facilitate easier rotation of headsets when not in use! Along with pre-bending wires!