Body in AlMg3 light alloy sheet, anodized (10 micron). Self-levelling platform with 2 side die-cast elements, complete with nylon rolls fit for sliding in light alloy rails, and 1 or 2 steel springs. Strong non-twisting bottom iron frame with epoxy finishing. 2 fixed and 2 swivelling wheels with non-marking rubber ring and zinc-plated housings.