Professional kit includes long-lasting aluminum adapters for US and metric fittings. US adapters: Two 3/8-24, two 7/16-24, two 9/16-18, two 9/16-20, and two 1/2-20.  Metric adapters: four M10 x 1.0, four M10 x 1.25, two M11 x 1.5, two M12 x 1.0, two M12 x 1.5 and two M13 x 1.5.