United Scientific Supplies metric, black enamel, hooked weight set is designed for use with hanging balances, and for applications that include pressure, torque, and tensile strength testing (set of 9). Black-enamel coated cast iron is durable and corrosion-resistant. The set of nine weights includes two each of the 200g and 20g weights, one each of the 1,000g, 500g, 100g, 50g, and 10g weights, and a plastic storage case.Calibration weights are used to measure the weight or mass of an object using a balance or scale, or to calibrate other weights or instruments. Calibration weights can be certified or uncertified. Certified weights meet strict guidelines for accuracy and can usually be recertified. Certified weights are used in labs where a high degree of accuracy and repeatability is required. Uncertified weights are used where a lower degree of accuracy is required, including student laboratories, rough weighting operations, and measuring force. Hooked and slotted weights are often used to measure pressure, torque, and tensile strength, and to demonstrate basic laws of physics. Calibration weights differ from lab weights, which are general purpose weights used to hold an object in place, similar to a paperweight. Science education products incorporate applied math and science principles into classroom projects. Teachers in pre-K, elementary, and secondary classrooms use science education kits and products alongside science, technology, engineering, and math (STEM) curriculum to demonstrate STEM concepts and real-world applications through hands-on activities. Science education projects include a broad range of activities, such as practical experiments in engineering, aeronautics, robotics, energy, chemistry, physics, biology, and geology.United Scientific Supplies distributes classroom and professional laboratory equipment for the fields of physics, chemistry, and biology. The company, founded in 1984, is headquartered in Waukegan, Illinois. What’s in the Box?1,000g500g200g (2)100g50g20g (2)10gPlastic storage case