Features: 1. This hole opener has a positioning center drill, which needs to be manually installed and tightened; 2. During the drilling , since the center positioning drill is cutting , and after it is in place, the center drill will play a positioning role at the end; 3. When cutting continuously, please select a lower speed; 4. In order to prevent chipping, please do not let the cutting edge of the hole opener collide violently with the cutting material instantly; 5. It is necessary to add water or cold cutting fluid to cool down, otherwise there is a risk of burning the drill bit; 6. The operator should wear protective glasses to protect the eyes. 7. When working for a long time, it is necessary to plug earplugs to reduce the of noise; 8. The hole opener is in a hot state after long-term , and care should be taken to avoid burning the skin when replacing it; 9. After use, apply anti-rust oil for longer service life. Specification: Name: bimetal hole saw Material: 2 Steel Color:green Size:16/18/20/22/25/28/30/35/38/45/50mm 2 steel has high toughness, high hardness, strong wear resistance and cutting ability. Applicable equipment: handle type, hand drill, bench drill It is suitable for punching a variety of materials: PVC board, plastic, wood board, gypsum board, iron sheet, aluminum alloy. Package Contents: 1*hole saw Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data. _x000D_ _x000D_