Lightweight is an understatement, or maybe an overstatement... Let's just say that it doesn't get much lighter than this. The Extralite UltraRear SX Rear Hub is just about the lightest roadworthy rear cassette hub on the planet.

Weight: 20h/134gr. 24h/135gr. 28h/136gr.
Material: special AL7075TX & GRD5 Titanium.
External Bearings: 6803-SRS/6803-2RS ABEC5 cartridges.
Internal Bearings: 6903-SRS ABEC5 main axle & Ertalite® bushing.
Compatibity: Shimano/Sram, Campagnolo, 10&11 speed compatible.
Axle construction: multishaped 17mm milled to micro tolerances.
Body construction: 3D multiaxial machining all in 1 stage.
Finishing: black anodized body, "hart-coated" axle-ends.
Micro-tuner: quickest bearing preload system.
Freewheel: Hyper engineered 2pawls OR-Drive.
Graphics: laser etched.