Genuine patented Aurigan bits are manufactured only by Herm Sprenger. Aurigan is a perfect mixture of materials(85% copper, 4% silicon and 11%zinc).Aurigan has high oxidation properties and provides a pleasant taste to encourage chewing activity andeasy acceptance of the bit. TheHerm Sprenger HS Aurigan Weymouth features avery slight arch for full palate clearance. TheHerm Sprenger HS Aurigan Weymouth is offered in mouth sizes 5", 5 1/4" or5 3/4". 16mm Aurigan mouth. 13cm stainless steel shanks with 7cm lower shank measurement.