Feature: 1. WEAR RESISTANT MATERIAL: Concrete rebound test hammer body is made of excellent stainless steel material, rustproof, wear resistant, possess high elasticity, fall resistant 2. ACCURATE AND CLEAR: The friction between the pointer shaft and the pointer slider is uniform, the index is accurate and clear, and the label is easy to read and understand 3. APPLICABLE SCENARIO: Concrete test hammer can be used to test the concrete strength of building wall, roads or bridges, not applicable to tile or brick wall 4. PORTABLE AND STABLE: The rebounded hammer tester is lightweight and portable. The internal excellent spring has good resilience and is durable, better protect the product 5. COMPLETE ACCESSORIES: The package include schmidt test hammer, grindstone, portable case, springs, screwdrivers, washer, etc. easy for you to install and use Specification: Item Type: Concrete Rebound Test Hammer Material: Stainless steel Nominal Energy: 2.207J Friction Force of Pointer: 0.5-0.8N Radius of Spherical End of Impact Rod: Approx. 25mm / 0.98in Stiffness of Impact Spring: 7.85N/m Working Length of Spring: Approx. 61.5mm / 2.42in Steel Anvil Calibration Value: 80±2. Package List: 1 x Concrete Rebound Test Hammer1 x Sandpaper2 x Spring2 x Screwdriver1 x Washer1 x Storage Box1 x Storage Case