Features: Size: drill bit diameter: 3mm/4mm/5mm; blade length: 48mm/60mm/70mm. Suitable for a plate in wood, plastics, aluminum, and iron, wall excluded. Made of high-speed steel, which is wear-resistant and durable. A 135-degree blade design makes it convenient to remove chips. With a 1/4 hex handle, it will not slip out of your hands easily. Any problems, feel free to contact us. Honor to serve you!