NiB-X Fire Control Group AR15/AR10
NiB-X Fire Control Group AR15/AR10, The WMD Guns' Fire Control Group, NiB-XA(R) gives you a good value for your money. These parts will give a long service life under the stress and friction of repeated use. WMD's NiB-X nickel boron treatment is harder and more resistant to wear than other nickel boron fire control groups.