The nRF21540 DB consists of the nRF21540 development kit (DK) and the nRF21540 evaluation kit (EK). The nRF21540 DK is the perfect tool to develop products that require the range extension capabilities or link budget improvements provided by the nRF21540 RF front-end module (FEM). The nRF21540 EK can connect to lab equipment via SMA connectors to monitor the RF FEM’s performance.
Datasheet : NRF21540-DB