EmonTx V3 with pre-fitted WiFi adapter. Can be used to post data to emoncms.org or another emoncms server directly from an emonTx without a separate base-station.
User Guide: Using the emonTx v3 with the ESP8266 Huzzah WIFI module
Forum post: Using the emonTx v3 with the ESP8266 Huzzah WIFI module
Github: emonESP open-source firmware
Adafruit: Full technical spec, datasheet and PCB CAD files for Adafruit ESP8266 Huzzah WIFI