Our newest adapter will make it easy to attach a flat mount type rear stock, our machined vertical rail, Buffer tube threaded cap, rear stock or folder. Our new rear adapter ONLY fits the KG-99 and other similar firearms that DO NOT have the threaded rear disc behind the upper assembly. The adapter is two pieces, a machined rear non threaded disc to fit at the rear of the upper firing tube, also includes our rear adapter. The rear adapter offers two mounting locations for our buffer tube mount, folding buffer tube mount, any any of our flat mount rear stocks. Also, includes two vertical threaded holes to mount our rear machined rail to mount any rail mount rear stock or sling, claw type attachment. This part ONLY fits KG-99.