Feature:1. Application: The heavy duty M9x0.75 to 1/228 adapter is designed replacement for Sig Sauer 1911 22, GSG 1911 22, 5PK 22 and some others that have M9x0.75 threads.2. Flat Ridges Design: M9x0.75 to 1/228 thread adapter comes with flat ridges for easy installation removal with a wrench (not included), improving the operating efficiency.3. With Thread Protector: The M9x0.75 to 1/228 adapter is equipped with a 1/228 thread protector to protect the 1/228 thread for use without an accessory or for storage.4. Knurl Design: The 1/228 thread protector is professionally designed with fine diamond knurl, looks attractive and great, and features greater friction to prevent slip.5. Durable Construction: The M9x0.75 to 1/228 converter with thread protector is constructed from premium high carbon steel with black oxide finish, not easy to rust, highly durable in use.Specification:Item Type: M9x0.75 to 1/228 AdapterMaterial: High Carbon SteelPipe End Thread: M9 (9mm) x 0.75mmAdapter Outer Diameter Thread: 1/2-28Cover Fully Screwed in Length: Approx. 1.25in/3.2cmMaximum Diameter (with Protective Cap Installed): Approx. 5/8in / 1.59cmFitment: For Sig Sauer 1911 22, GSG 1911 22, 5PK 22 and some others that have M9x0.75 threads..Package List:1 xM9x0.75 to 1/228 Adapter