Ryno RPS-HD2 Heavy Duty Paving Support Shim 180mm Diameter x 2mm Polypropylene. The Ryno HD paving support levelling shim provides support between paving slabs and RYNO RPS-HD15 Heavy Duty Stackable Paving Support Pads. Supports can be stacked and combined with shims to achieve exact height requirement. Manufactured with holes and slots for drainage and vertical spacers for even spacing of slabs. Manufactured from heavy duty, chemical resistant, solid polypropylene.