The Encardio-rite EDS-21V series of vibrating wire strain gages are designed to measure large strains upto 5000 micro-strains.Model EDS-21V-E embedment strain gage is used to measure strains in concrete mass. It is designed to measure strain in underground cavities, tunnels, buildings, concrete and masonry dams etc. Model EDS-21V-E embedment strain gage has stainless steel flanges at either ends and is suitable for embedment directly in concrete.Any deformation in the concrete mass causes the two end blocks to move relative to one another, thus changing the tension in the wire, resulting in a corresponding change in its frequency of vibrations. It is similar to model EDS-20V-E embedment strain gage, except that it is used to measure large strains upto 5000 micro-strains. Model EDS-20V-E can measure up to 3000 micro-strains.