Boat: synthetic; rail: aluminium; bearings: steel; wheels: polyurethane Imported BOA System - Tightens or loosens the boot with a twist of a knob Stability Plus Cuff - Provides the right amount of support, flexibility, reliability and comfort to have a good time Die-Cast Aluminum Frame - Responsive and stiff die cast aluminum for acceleration, speed and control. ILQ 7 Bearings - A classic inline skate bearing that has a 608 standard hub and will allow you to skate just a little bit faster than you are used to. 90mm 83A Wheels