Standard 40PIN GPIO extension header, supports series boards, Nano. Supports SMS, GPRS, DTMF, HTTP, , , email, etc. Bluetooth 3.0, supports data transferring through Bluetooth. Onboard voltage level translator, 3.3V by default, switch to 5V via jumper. 2x for indicating the module working status. slot for 1.8V/3V 2x for indicating the module working status. Baudrate auto detection (1200bps ~115200bps). Control via AT commands (3GPP 27.007, 27.005, and SIMCOM enhanced AT Commands) Baudrate auto detection (1200bps ~115200bps). Supports SIM application toolkit: GSM 11.14 Release 99;UART interface, for connecting host control boards like /STM32 UART interface, for connecting host control boards like for /STM32. Supports SIM application toolkit: GSM 11.14 Release 99. color:Blue Material:PCB size:65 x 30.5mm Package Contents: 1 x SIM800C GSM/GPRS HAT 1 x GSM Antenna 1 x Bluetooth Antenna 1 x USB type A plug to -plug cable 1 x RPi screws pack (2pcs) Only the above package content, other products are not included. Note: Light 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.