If you have a custom PCB design and you'd like to add a little Bluetooth® Low Energy, this module is ultra compact and easy to use. It contains a Nordic nRF52840 Cortex M4 chip that comes integrated with Bluetooth® Low Energy radio, USB, as well as most of the supporting circuitry and even a chip antenna. The whole thing is in a tin and comes with FCC, CE, and TELEC certifications.