Quad : Our quad skates feature lace lock closure system and glass reinforced nylon Zytel frame. Breathable liner with memory foam and shock-absorbing insole. Size : 4-12 Shell : BASF Pu 64D Chassis : Du-pont Zytcl 8018 Trucks : Alum.material Bearings : Abec-1 608ZZ Wheels : 58 x32 mm H.R. Stopper : Rubber, back Liner : Breathable memory foam