A Watt balance at NIST (IMAGE) American Institute of Physics Caption NIST's watt balance is a powerful measuring tool that is aiding in the redefinition of the kilogram Credit NIST Usage Restrictions This image may be used only with appropriate credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.