1. There is no external IC card input to avoid human deliberate damage 2. The prepayment system can also control with timing and amount of use. 3. Long operation life, interference-resistant, and attack-resistant. 4. Information transmission: as the information carrier, non-contact IC card (radio frequency) transmits about prepayment consumption, code and so on. 5. Real-time calculation: according to the amount of the prepayment and consumption, LCD module displays the real-time calculation of the balance. 6. Vocal-light instruction: operation finishing, balance overflow could be instructed in vocal-light signals. 7. Automatically control on/off: according to the data of water prepayment and consumption, the valve of the water meter shall be auto-controlled on or off.