Proven time and again in World Cup race conditions, the ZERØ Ceramic bearings are the ultimate race day weapon. Oversized Grade 3 balls roll on races which are ground to a mirror finish after receiving Magnetite and then Cryogenic treatments for hardness and longevity. More durable and with even lower rolling resistance than any 2RS bearings, they come closer to that magic “zero” rolling resistance number. Enduro Bearings uses Silicone seals which are more slippery than rubber seals used by other ceramic bearing suppliers. We get more email and blog feedback on the ZERØ's than any other bearing, describing the noticed difference in downhill rolling speed. And they win the independent wattage output tests when stacked against the competition. If you want to buy raw speed, ZERØ bearings are it.