LANGRY’s GZII Testing Anvil is essential for accurate rebound hammer calibration. Placed on a rigid horizontal surface, it ensures precise calibration vertically or horizontally. The average calibration value of the N-type concrete rebound hammer (2.207J) is [R] = 80±2. Furthermore, its Rockwell hardness of HRC 58-62 guarantees durability. The testing anvil is usually kept in a dry and dustproof place to prevent corrosion. The test surface shall not be knocked against at will to ensure the inspection tool’s standard state.