Chris King DropSet 2 Headset. - Patented GripLock retention design for exclusively reliable headset adjustment - 42mm 45x45 upper bearing - 52mm 45x45 lower bearing - Compatible with King baseplate and 45 degree integrated crown races - Crown Race: 30 - S.H.I.S. Stem Clamp Diameter: 28.6 Threadless - Bearing Type: Cartridge - S.H.I.S Lower: IS52 - S.H.I.S Upper: IS42

These baseplates are the foundation that keeps Chris King headsets turning with legendary smoothness. Manufactured from high-quality stainless steel or titanium, Chris King makes replacement baseplates for all standard sizes and a number of ingenious solutions for those that need something a little special to make their headset work. - Engineered and manufactured in Portland, Oregon USA - Devolution baseplates are a stainless steel solution that allow Chris King headsets to adapt to a wide variety of steerer tube sizes - 30.0mm for 1.5 lower bearing and 1 1/8" steerer