This part of ISO 6360 presents a number coding system for dental rotary instruments and accessories, and provides guidance with regard to its interpretation and use. This part of ISO 6360 specifies the code numbers for materials used for the working parts of instruments, the coating and the binding of abrasives for instruments. This three-digit number forms the first group of three digits in the 15-digit overall number. This part of ISO 6360 further specifies the code numbers for shanks, handles, or bore diameter of unmounted instruments, and for the overall lengths of instruments. This three-digit number forms the second group of three (two plus one) digits in the 15-digit overall number. In Annex A several examples of complete 15-digit identification numbers are given to demonstrate the number coding system, including examples of three (additional) optional digits (16 to 18) for diamond instruments. NOTE In addition to terms for rotary instruments and accessories used in two of the three official ISO languages (English, French and Russian), this part of ISO 6360 gives the equivalent terms in the German language; these are published under the responsibility of the member body for Germany (DIN). However, only the terms given in the official languages can be considered as ISO terms.