Like Ceramic Hybrid, Zero Ceramic use a combination of ceramic (Silicon Nitride - Si3n4) balls and steel races, except they are of higher Grade 3 quality. The races are also black oxide treated and ground toa mirror finish which prevents corrosion and provides near perfect efficiency and tolerances.
Bearing Code - 6805
Dimensions - 25mm x 37mm x 6mm (6mm width fits Campagnolo Ultra Torque)