... Jack, U-head, Universal JackSolid Jack: 30mm, 32mm, 34mmHollow Jack: 34mm, 36mm, 38mmSurface: Painted, Electro Plated, Hot dipped GalvanizedAny length is availableSome popular sizes ... for reference:Jack BaseBase PlateM30(solid)*600mm120*120*4mmM32(solid)*600mm140*140 ...