Portable Hardness Testers are provided with USB interface for efficient and easy connecting to the computer. They are designed to store more than 600 average values for future references. They are equipped with voltage and under voltage display along with voltage automatic shutdown function. In addition to this, these Portable Hardness Testers are provided with modern indication software calibration function and replaceable large capacity lithium battery. According to the needs of the clients, they can be designed with Bluetooth print fun and wireless data transmission features.