This box of standard weights is absolutely essential for general laboratory work. Includes 1 each of 1g, 5g, 10g, 50g, 100g, 500g, 1000g and 2 each of 2g, 20g, and 200g masses. Plated brass weights (masses) with knobs in a wooden case with a hinged lid. Calibrated according to tolerances specified by International Organization for Legal Metrology, Class M2. Fractional weights are not included.