We thought Zipp would stop tinkering with its 900 Disc Tubular Road Wheel. But this latest version is 90g lighter than the previous generation Zipp disc. It still has only 19mm of frontal area, so it's still nearly invisible to the wind. It still has a dimpling pattern that's specific to the 900, which helps smooth the air flow in order to minimize drag. Its Aerodynamic Boundary Layer Control ABLC carbon fiber skins are embossed with over 4900 golf ball like dimples in five different sizes that are patterned to force the airflow to form less turbulent boundary layers. In other words, you get less drag in all wind angles, as well as less buffeting of the disc in crosswinds. The result is the fastest disc that Zipp's ever tested. The Zipp 900 tubular disc wheel is only available as a tubular. The wheel was constructed from two sheets of hand laid carbon fiber with a honeycomb core. For the standard disc, there's a track adapter so the wheel is able to be used as a fixed gear. The cassette body is also able to come with Campagnolo splines or ShimanoSRAM splines for the appropriate cassettes. The hub bearings are capable of being upgraded to ceramic. The disc comes with an angled valve adapter so that the tire can be pumped up and six Zipp jersey patches for covering the valve cutout. The Zipp disc weighs 935g in the 700c version. Skewer is not included. Please Note: Zipp's Tangente Platinum Pro and cork brake pads are designed specifically for use with its carbon tubulars. Use of brake pads other than these is highly recommended against and will void the wheel warranty. The Zipp 900 Disc Tubular Road Wheel is available as a 700c rear wheel and in the color Black with either Black or White labels. Please note that this wheel is only available in a tubular configuration, and with your choice of either a Campagnolo or ShimanoSRAM 11 speed compatible freehub body.