We've taken the popular and made it even better! Now the main chip is an nRF52840 microcontroller which is not only more powerful, but also comes with Bluetooth Low Energy support for wireless connectivity.
The board is round and has alligator-clip pads around it so you don't have to solder or sew to make it work. You can power it from USB, a AAA battery pack, or with a Lipoly battery (for advanced users). Circuit Playground has built-in USB support. Built in USB means you plug it in to program it and it just shows up, no special cable or adapter required. Just program your code into the board then take it on the go!