Sets contain keys labeled with the manufacturer code that can only be used with the corresponding manufacturer and some universal drill keys. Keys are also labeled with connection sizes S, M, and L that indicate which drill key is suitable for each specific CEREC^® guide block, as well as the inside diameter of the drill key in mm. Universal drill keys are not labeled with a manufacturer code and are used in conjunction with the labeled keys in the key set. Made of grade 1.4301 stainless steel. Supplied unsterile.