Holds rods of 10mm or 12.5mm diameter Interchangeable tapered wedge inserts are easy to swap out Spring loaded center jack Vice-like grip prevents slip of burettes Corrosion resistant polypropylene construction Eiscos polypropylene double burette clamps come with easy-to-change wedges that hold rods of 10mm or 12.5mm diameter. Rugged yet lightweight, they are equipped with a spring-loaded jack that locks firmly onto burettes to prevent slip. Non-metal build reduces the chance for accidental impact breaks of glass burettes.