Fsa xtreme pro is49 lower headsetthis headset features a hard wearing aluminium 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 34.8g. 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 fsa headset category premium fork steerer compatibility 1 1 4 tapered forks lower 1 1 4, 45° 45° acb gray seal higher quality seals laser etched graphic to easily identify the headset spec plus provides a higher quality look for tapered 62mm od head tube is49 part number 121 0020000001 weight 34.8g approxbuy fsa components from chain reaction cycles, the world's largest online bike store.