Compliant with Bluetooth 4.0 BLE standard Support intelligent door lock app for opening doors Built in RTC clock chip Built-in antenna Built in passive switch (relay) Note: 1. Below the minimum operating voltage, it may cause the module to malfunctionExceeding the maximum operating voltage may cause module damage 2. Generally, modules are in a sleep state and only switch to other states when unlocking with the app 3. Extreme environments can cause modules to malfunction Note: The factory batches are different. If there is a slight difference in appearance, it does not affect the use. Colour: Green Material: Plastic Size: 38x27mm (excluding lines) Package Contents: 3 x Electronic Lock Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.