IADC Roller Cone Bit Classification Codes System
The IADC roller cone drilling bit classification charts are often used to select the best bit for a particular application. These charts contain the bits available from the four leading manufacturers of bits. The bits are classified according to the International Association of Drilling Contractors (IADC) code.  The position of each bit in the chart is defined by three numbers and one character. The sequence of numeric characters defines the “Series, Type and Features” of the bit.
https://www.drillingmanual.com/classification-of-roller-cone-bit/