产品名称（Product Name）：Valve-controlled IoT water meter (copper shell)

功能（Function）：

1.1 Valve closing function for arrears: When the user's water volume is used up, the background software system can issue a valve closing command to cut off the water source and remind the user to buy water. (Background software support is required)

1.2 Overdraft function: When the water meter is instructed to close the valve by the background system, pressing a button on the water meter once can open the water meter valve and continue to use water for three days. After three days, the valve will be permanently closed. At this time, the water meter valve can only be opened after recharging and purchasing water and the background software system issues a valve opening command.

1.3 Protection function: When the water meter encounters magnetic interference, the water meter will automatically close the valve; at the same time, the water meter will record the interference information.

1.4 Battery undervoltage reminder function: When the battery power is low, the valve will not close, and water can continue to be used. The "low power" fault will be reported simultaneously to remind the user to contact the management department to replace the battery; after the new battery is replaced, the reported "low power" fault will be automatically cleared.

1.5 Power-off valve function: When the water meter is powered off, the valve does not close by default (optional: set the power-off valve closing function); after the battery is re-inserted, the valve returns to the state before the power failure.

1.6 The display mode of mechanical metering does not change, which is convenient for users to intuitively check the water consumption.

1.7 No wiring is required, direct communication automatically uploads data to the server, and the metering is accurate.

主要技术参数（Main technical parameters）：

2.1 Maximum allowable working pressure: equal to 1.0MPa.

2.2 Maximum allowable working temperature: 30℃ for cold water meter and 90℃ for hot water meter.

2.3 Metering characteristics: The accuracy level is level 2. In the water temperature range of 0.1℃ to 30℃, the maximum allowable error of the water meter in the high zone (Q2≤Q≤Q4) is ±2%, and the low zone (Q1≤Q＜Q2) is ±5%. When the water temperature exceeds 30℃, the maximum allowable error of the water meter in the high zone is ±3%, and the low zone is still ±5%.

主要机械参数（Main mechanical parameters）：