The DC type impact device of Mitech portable hardness tester,height: 86mm, weight: 50g,diameter: 20mm, has build-in DC impact body. The load device of the impact body is designed at the outside of the impact device. With small volume, DC type impact device is suitable for hardness measurement of the marrow parts (like holes, slits) of the workpiece with weight above 5kg, thickness above 5mm. It is widely used for the narrow parts of the installed machinery or permanently assembled parts, rapidly testing for multiple measuring parts in large range of the large-scale workpiece, hardness testing for gear tooth root and other slender narrow grooves or hole. It can realize the precise measurements for Leeb, Brinell, Rockwell and others.