LANGRY Penetration Mortar Strength Tester SJY-800B is suitable for masonry mortar strength testing. The penetration method is based on the relationship between the depth of nail penetration into the mortar and the compressive strength of the mortar, using the lever force method, compressing the working spring to load, storing potential energy, and instantaneously penetrating the nail into the mortar. A field detection method that measures the penetration depth of the nail and converts the strength by combining it with the relevant strength measurement curve.