JMPF 5/8-TP Steel Knurled 5/8-24 x .875 (7/8) OD x .625 (5/8) long Thread Protector Adapter 5.56/223 Made in the USA, not China like others Made from Steel, Black Oxide Finish .875 (7/8) OD x .625 (5/8) long x 5/8-24 thread Click on JMPF to view our other parts/sets