- M-type wrench tool is used for tightening and loosening collet chuck holder, simple to operate and improve your work efficiency. - These wrenches are treated with special technology, high hardness and wear resistance, making the surface easy to keep clean and not easy to rust. - The red anti-slip handle is ergonomic, anti-slip and wear-resistant, comfortable to handle, beautiful and practical. Designed to hold the wrench tightly and save on the amount of work required. - When you use the wrench, you have to tighten the wrench first and hold the end of the wrench with your hand. Tighten it clockwise, loosen it rotate counterclockwise. Suitable for lathe milling machine etc Specification: Type: M Type Model: ER16, ER20 Material: Steel, Rubber ER16 Wrench Size(Length x Open): Approx. 120 x 12mm ER20 Wrench Size(Length x Open): Approx. 132 x 17.2mm Package Includes: 1 x ER16 M Type Wrench Spanner 1 x ER20 M Type Wrench Spanner