This fast attach is all steel (not aluminum) and fits 1/2x28 barrel threads. The external threads are 13/16" and fits all of our filter kits (the 5", 7" and 10" kits). It assists in speed cleaning since you can screw the tube on & off quickly. It comes with a steel crush washer. This fast attach has three large discharge ports on the main body and six micro-ports for top discharge (which compensates for muzzle rise). The coating is black oxide which helps in resisting corrosion. All threads are PARELLEL threads, so your rifle threads are never damaged no matter how many times you remove or install.