Carver Surf Skate Bearings Abec 7 Built-Ins are the ultimate bearing for speed, performance, and durability. Built with hardened Rockwell C-65 grade steel and precision grooved inner races, these bearings provide an ultra smooth ride with low rolling rolling resistance, less overall friction, and a longer bearing life. The built-in spacers and speed rings allow for an easy and hassle free installation creating a solid and perfectly centered set up.