the meter is in accordance with technical regulation of jgj/t23-2001, used for testing of concrete compressive strength within the scope of 10-60mpa, with the system standard energy of 2.207j, and value indicating system of pointer direct reading. Our concrete resiliometer has been approved as recommended product for engineering construction by the ministry of construction. Item specifications length of pointer: 20.0±0.2 (Mm) friction of pointer: 0.65±0.15 (N) sphere semi diameter at the end of the flip rod: 25±1.0 (Mm) rigidity of flip tensioned spring: 785.0±40.0 (N/m) location of flip hammer’s hook release: “100” at the scale mark work length of flip tensioned spring: 61.5.0± 0.3(Mm) strike length of flip hammer: 75±0.3(Mm) hop location of the flip hammer: “0” at the graduated scale fixed value of steel anvil: 80±2 (our products are controlled between 80-81) package included concrete rebound hammer tester grindstone flip tension spring buffer spring screwdriver instruction manual.