Made out of zinc alloy, it's offen put inside the MDF board, or other wooden plate, it's usually used with screws, widely in wooden furniture industries.
1. Diameter: M4-0.7; M5-0.8; M6-1.0; M8-1.25; M10-1.5.
2. Length: standard size; there is not many choice for each diameter.
3. Material: zinc alloy.
4. Coating: upon request.