Nukeproof horizon bottom headset cupnukeproof's headsets feature titanium coated race bearings with stainless steel balls. The titanium coating has been applied using a method called 'physical vapour deposition,' pvd which helps to improve durability and overall structure and density of the bearings. Incredibly fine, this coating is only 0.000118rdquo thick and won't be damaged with wear or tear or corrode, thanks to the molecular bond from the pvd method. Whatsmore the race bearings have been abec 5 certified, making it the ideal addition.these bearings have been designed for use in the harshest weathers and have gone through various tests by the nukeproof team during development so they are 100% confident in their performance. To back this up nukeproof are offering a 5 year warranty on these headsets so you can be reassured your purchase will be a good one. All models feature a super tough black hard anodised finish, with laser etched graphics.features headset type specific bottom cup bearings replaceable, angular contact type graphics laser etched crown race split alloy finish hard anodised options internal and external includes crown race, top cap and bolt supplied reducer crown race for 1.5 1 1 8 sold separately modelheadtube internal diametersteererblack 1.1 8 ex34 30 b134mm1 1 8black 1.1 8 ex44 30 b544mm1 1 8black 1.5 ex49 40 b749mm1.5black 1.5 zs56 40 b856mm1.5 buy nukeproof components from chain reaction cycles, the world's largest online bike store.