The NELD-ES731 Contactless Contraction and Expansion Deformation Tester developed by Beijing Nai'erde Company is designed for measuring the shrinkage and expansion deformation of early-age concrete. It can also be used to determine the shrinkage and expansion deformation of concrete under unconfined conditions. The product measures the displacement of a target embedded in concrete using an electrical eddy current sensor, and its high-precision processor can accurately measure the deformation data of early concrete shrinkage. The main unit features an 8-inch color touch screen, easy operation, and a user-friendly interface; the data analysis software offers bidirectional data analysis capabilities; and the measuring fixture structure is scientifically designed with exquisite processing. The product has received unanimous praise from users and is a reliable choice for scientific research institutions and quality control units.