We manufacture various pdc bit for different drilling application. This type you saw is for drilling coal or geological drilling. The size is 55mm, 65mm, 75mm, 85mm, 94mm, 113mm, 133mm, 153mm, 171mm, 219mm, 245mm, 273mm etc. Your design could be made according to your requirements and it can satisfy different customers specific needs. We insist on honesty to provide customers high performance products with competitive price.