The Ohaus metric calibration weight set meets International Organization of Legal Metrology (OIML) Class F1 specifications and is designed for calibrating other weights, or electronic balances and scales. The weight is constructed of stainless steel for stability, resistance to corrosion, and low magnetic susceptibility. The weight meets OIML R111 Class F1 specifications for use calibrating high-precision top loading balances with a readability as low as 0.01g to 0.001g. The set of eight weights includes two weights each of 20g, and 2g, and one weight each of 50g, 10g, 5g, and 1g, tweezers, and a protective 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.Ohaus manufactures scales and balances for laboratory, educational, retail, food, and jewelry applications. The company, founded in 1914, is headquartered in Parsippany, NJ. What’s in the Box?Set of eight OIML Class F1 calibration weights 50g 20g (2) 10g 5g 2g (2) 1g Tweezers Protective case