Rival Arms RARA300001D Thread Protector 9mm Luger Stainless PVD 416R Stainless Steel 1/2"-28 tpi
https://www.tandktactical.com/shop/788130029657-rival-arms-rara300001d-thread-protector-9mm-luger-stainless-pvd-416r-stainless-steel-1-2-28-tpi-27045
https://www.tandktactical.com/web/image/product.template/27045/image_1920?unique=242bc56
The Rival Arms Thread Protector is CNC-Machined from 416R stainless steel billet results in superior corrosion resistance and durability.