Ceramic bearing upgrade kit for Mon Chasseral, XRC and XMC 1200 wheels Custom made for DT Swiss the SINC system offers the very pinnacle of bearing quality and precision Just because a bearing says 'ceramic' doesn't mean it is a quality product, it all comes down to the grade of material used and the tolerances of the bearing's construction The balls in SINC bearings are made in Japan from Si3N4 Silicon nitride; the toughest and smoothest bearing material available and certified to be as perfectly round as modern production techniques allow Combined with DT's custom designed carriers and seals this produces a bearing with class leading low rolling resistance and durability Kit contains main bearings for both front and rear hubs, 4 in total Comes in a presentation tin with USB stick containing detailed installation instructions To ensure maximum performance and durability we strongly recommend that SINC bearings are installed by trained mechanics using the DT Swiss hub servicing tool kitt