Features 1. Application: 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 other models with M9x0.75 threads. 2. Flat Ridges Design: The M9x0.75 to 1/2-28 thread adapter features flat ridges for easy installation and removal using a wrench (not included), enhancing operational efficiency. 3. Thread Protector Included: The adapter comes with a 1/2-28 thread protector to safeguard the 1/2-28 threads when no accessory is attached or during storage. 4. Knurl Design: The 1/2-28 thread protector features a fine diamond knurl pattern for improved grip, reduced slippage, and a professional appearance. 5. Durable Construction: Made from premium high-carbon steel with a black oxide finish, the M9x0.75 to 1/2-28 adapter with thread protector resists rust and ensures long-lasting durability. Specifications Item Type: M9x0.75 to 1/2-28 Adapter Material: High Carbon Steel Pipe End Thread: M9 (9mm) x 0.75mm Adapter Outer Diameter Thread: 1/2-28 Overall Length (with cover fully screwed in): Approx. 1.25 in / 3.2 cm Maximum Diameter (with protective cap installed): Approx. 5/8 in / 1.59 cm Compatibility: Designed for Sig Sauer 1911 22, GSG 1911 22, 5PK 22, and other firearms with M9x0.75 threaded barrels. Package List 1 x M9x0.75 to 1/2-28 Adapter