●Package Included: This set of weight sets has 17 calibration weights in total, 13 different specifications in total, which can be used in different occasions. Equipped with tweezers and a plastic storage box, which is easy to use and store. ●High Precision: Permissible Error: +/- 0.003g ●Widely Application: Perfect for digital jewellery scale, general laboratory, commercial and educational, digital pocket scale, jewelry carat scale, diamond scale, precision balance test, etc ●Counterweight: The counterweight of this weight set is cylindrical, with a raised part on the upper end, which is easy to grasp and easy to operate. ●Counterweight: The counterweight of this weight set is cylindrical, with a raised part on the upper end, which is easy to grasp and easy to operate.