A full complete set up of boat trailer rollers full set bunk conversion kit full set up, enough to transform even the largest boat trailers to rollers. Comprising of a total of 36 nylon wobble rollers with non marking polyurethane tyres for life long use, fitted onto fully galvanized boat trailer rollers spindles and carriages. Now comes with universal brackets and u bolts that will fit all boat trailers. Larger carriages are fitted near to the boat stern and smaller ones near the boats bow. To save work these boat trailer roller carriages can be fitted straight onto the existing stems on your boat trailer. Stems are 30mm x 30mm box section, Boat trailer roller carriages are 40mm x 40mm box section