Fsa xtreme pro is42 lower headsetthis headset features a hard wearing aluminium top cover construction, which makes it ideal for everything from clocking up the miles on your road bike to shredding the trails on your mountain bike. Fsa has also equipped this model with robust stainless steel bearings, so you can enjoy a durable, smooth action as you conquer every journey. Engineered for performance, this versatile headset weighs in at only 34.7g. This means that you'll also benefit from its incredible strength and smooth rotating performance, without worrying about adding any unnecessary weight to your ride.features material aluminium bearing materialstainless steel use road, mtb fork steerer compatibility 1 1 8 tapered forks lower 45° 45° acb grey seal higher quality seals laser etched graphic to easily identify the headset spec plus provides a higher quality look for tapered 46mm od head tube is42 30 part number 121 0026000454 weight 34.7gbuy fsa components from chain reaction cycles, the world's largest online bike store.