1. Usage: The heavy-duty M9x0.75 to 1/2-28 adapter is designed as a replacement for Sig Sauer 1911 22, GSG 1911 22, 5pk 22, and certain others that have M9x0.75 threads. 2. Flat Knurled Design: The M9x0.75 to 1/2-28 thread adapter comes with flat knurls for easy installation and removal with a wrench (not included), enhancing operational efficiency. 3. With Thread Protector: The M9x0.75 to 1/2-28 adapter is equipped with a 1/2-28 thread protector to safeguard the 1/2-28 thread without an accessory or for storage. 4. Knurl Design: The 1/2-28 thread protector is professionally designed with fine diamond knurling, offering an attractive appearance and a good grip, with larger surface area to prevent slipping. 5. Durable Construction: The M9x0.75 to 1/2-28 converter with thread protector is built from premium high-carbon steel with a black oxide finish, making it resistant to rust and highly durable. Item Type: M9x0.75 to 1/2-28 Adapter Material: High-Carbon Steel Barrel End: M9 (9mm) x 0.75mm Adapter Outer Diameter Thread: 1/2-28 Protector Fully Screwed Length: Approx. 1.25in/3.2cm Maximum Diameter (With Protector Cap Installed): Approx. 5/8in/1.59cm Fitment: For Sig Sauer 1911 22, GSG 1911 22, 5pk 22, and certain others that have m9x0.75 threads. 1 x M9x0.75 to 1/2-28 Adapter