This carbide forstner bit has a 2-1/4" cutting diameter and a 10mm shank compatible with all standard drill and drill press chucks. Forstner bits are a great choice for cutting clean and accurate flat bottom holes. Except for the slight notch created from the centre spur, the resulting holes are clean and smooth. The middle spur helps centre the bit, while the outer rim helps maintain the bits position when drilling angled or overlapping holes. Carbide blades add longevity to the bits life, making it a good choice for production shops.