The Rice Lake U.S. customary (also referred to as English and avoirdupois), stainless steel, double-hooked test weight has a sliding hook that can be chained to other hooked weights or set flat, a density of 7.84, and is designed for use with hanging balances, and for applications including pressure, torque, and tensile strength testing. The weight is constructed of stainless steel for stability, resistance to corrosion, and low magnetic susceptibility. The weight meets American Society for Testing and Materials (ASTM) E617, Class 6 specification for calibrating brass student weights.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.Rice Lake Weighing Systems manufactures weight-related and process-control equipment for use in research, scientific, and quality control labs. The company, which was founded in 1946 and is headquartered in Rice Lake, WI, meets International Organization for Standardization (ISO) 9001:2008 standards, and is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) to ISO/IEC 17025:2005.