It doesn’t even run on 3.3 V! Use a Li-Po battery or a DC-DC buck converter instead.

Keep in mind that the SIM800L chip has an operating voltage range of 3.4 V to 4.4 V, so connecting this module to the Arduino’s 5V output is probably going to cause damage to the module.

Integrated 802.11b/g/n WiFi 2.NET pin is where you can solder the helical antenna that comes with the module.

Xtensa® Single-Core 32-bit LX6 Microprocessor (up to 240MHz).

CHG - Yellow battery charging indicator.

2-pin JST Connector for a LiPo Battery (not included).

Up to two UARTs (only two are configured by default in the Arduino IDE, one UART is used for bootloading/debug).

Up to two I 2C Busses (only one is configured by default in the Arduino IDE).

Up to three SPI Busses (only one is configured by default in the Arduino IDE).

SparkFun Thing Plus - ESP32 WROOM Features This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. The SparkFun Qwiic Connect System is an ecosystem of I 2C sensors, actuators, shields and cables that make prototyping faster and less prone to error.

Thanks to the onboard ESP32 WROOM module, the SparkFun Thing Plus features 16MB of flash memory, 520kB of internal SRAM, an integrated 802.11 BGN WiFi transceiver and dual-mode Bluetooth capabilities, and a JST connector to plug in a LiPo battery. The ESP32 Thing plus integrates a rich set of peripherals, ranging from capacitive touch sensors, SD card interface, Ethernet, high-speed SPI, UART, I 2S and I 2C.

You can even program the Thing through the Arduino IDE by installing the updated ESP32 Arduino Core. The Thing does everything from turning on an LED to posting data with your chosen platform, and can be programmed just like any microcontroller. Why the name? We lovingly call it the “Thing” because it's the perfect foundation for your Internet of Things project. To make the Thing Plus even easier to use, we've moved a few pins around to make the board Feather compatible and it utilizes our handy Qwiic Connect System which means no soldering or shields are required to connect it to the rest of your system! At the core of this module is the ESP32-D0WDQ6 chip which is designed to be both scalable and adaptive. Espressif's ESP32 WROOM is a powerful WiFi and Bluetooth MCU module that targets a wide variety of applications. The SparkFun ESP32 Thing Plus is the next step to get started with Espressif IoT ideations while still enjoying all the amenities of the original ESP32 Thing.

Fritzing esp32