More parts mean more chances for failure and creaking, so Cane Creek designed the 40 Series ZS4428. 6 Tall Top Assembly Headset to be used without spacers, so you increase strength, decrease the likelihood of creaking, and get 15mm of rise in one convenient and durable package. Cane Creek built the headset cups from strong T6 alloy and stashed away black oxide cartridge bearings inside. The ZS's races and bearing are made of steel that's been treated to prevent corrosion, and the cartridges are finished with Cane Creek's Split Lip seal, which provides extra protection against dirt while locking in grease. There are additional seals at the crown race and top, and a Clip Seal in the upper section to prevent all the smaller parts from falling apart during assembly.