Introduction: NRF52840 is a ProMicro-alternative development board that is compatible with for Nice! Nano. Its pins are the same as ProMicro, which means it can be used with for almost any ProMicro-keyboard. The NRF5280 development board has a 3.7V lithium battery interface and a software switch that can cut off the power of the LED. When turned off, the standby power consumption can reach 1mA. nRF52840 is a high-performance, low-power wireless SoC chip launched. It supports multiple wireless protocols, including Bluetooth 5, Thread, Zigbee, ANT, and 2.4GHz. The nRF52840 chip uses an ARM -M4F processor, clocked at 64MHz, with built-in 1MB of flash memory and 256KB of RAM. It also has a variety of peripherals, including ADC, PWM, SPI, I2C, UART, USB and GPIO, etc. In addition, nRF52840 also supports a variety of security functions, such as encryption, SHA-256 hashing and True Random Number Generator (TRNG). Product Parameters: Powerful wireless capabilities: Bluetooth 5.0 onboard antennaPowerful CPU: nRF52840 chip uses ARM -M4F processor, clocked at 64MHz, built-in 1MB flash memory and 256KB RAM Battery charging chip: supports lithium battery charging and discharging Power consumption: standby power consumption can reach 1mA for ProMicro-NRF52840 Material: PC,Metal colour: Black Package Contents: 2 x NRF52840 Development Board 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.