Seeed nRF51822 Module - Seeed Studio

The Seeed nRF51822 Module is a low cost ARM cortex-m0 based module for Bluetooth® Smart designs with the nRF51822 SoC. The module gives access to at most 23 GPIO pins via pin pads and incorporates an on board PCB antenna to minimize material cost but also with a good performance.The application engineers can easily apply the module for theirs application without worrying about the specific impedance matching or soldering fine pitch related radio designing issues.
Features
Multi-protocol 2.4GHz radio
32-bit ARM Cortex M0 processor
256kB flash/16kB RAM
Programmable output power from +4dBm to -20dBm
Flexible and configurable 23 pin GPIO
Wide supply voltage range (1.8 V to 3.6 V)
RSSI