Type A & Type D: Can be used to measure the Rubber, Hard-resin, Glass, Thermoplastic plastics, Printing plates, ... Battery: 1.5V battery Type A & Type D: Can be used to measure the Rubber, Hard-resin, Glass, Thermoplastic plastics, Printing plates, ... Fiber, etc. Type C: Can be used to measure the Hardness of Foam, Sponge, Shoes with incorporates material, etc.