1. Powerful function: T-Call V1.4 ESP32 wireless communication module with FPC antenna and SIM800L integrates ESP32 WROVER-B and SIM800L modules, offering comprehensive features and functions. 2. Easy to use: Features CP210X USB-to-serial chip for seamless connection to computers or devices via USB, enabling fast and stable data transmission. 3. Integrated design: Combines ESP32 WROVER-B and SIM800L modules into a compact unit, allowing users to leverage the capabilities of both modules on a single platform. 4. Battery powered option: Includes lithium battery charging and discharging circuit with overcharge and over-discharge protection. Supports simultaneous operation and charging, enhancing portability and convenience. 5. Wide compatibility: Supports low-power voice, SMS, and data transmission, making it suitable for various applications. Power supply voltage: DC 3.6V–5V (5V input via TYPE-C port) Onboard lithium battery interface with integrated charging and discharging circuit Module can operate while charging the battery Charging current: 500mA Supports WiFi and Bluetooth communication SIM card slot supports NANO SIM cards from major GSM networks Supports voice, SMS, and data transmission Dual onboard audio ports: microphone-in and audio-out Onboard blue LED indicator on IO13 pin Color: Black Material: Plastic Size: 7.5 x 3 x 1 cm Package Contents: 1 x Bluetooth module board (set) Note: Light reflection and display differences may cause slight variations in color between the image and the actual item. Measurement error allowed is +/- 1–3 cm.