Coppermade Flowmeter sensor 2 to 50 liters/min for 1" inch pipe (DN25)
Coppermade Flowmeter sensor 1 to 30 liters/min NPT 3/4
Coppermade Flowmeter sensor 1 to 25 liters/min NPT 1/2
HAC-EMBee ZigBee module for wireless communication at 2.4GHz. Includes whip antenna.
GSM / GPRS voice data SIM900 Arduino Shield Mobile Cellular
GSM/GPRS Module + GPS: Compact cellular Voice, Data and Global Position!
GPS / Glonass / Galileo Positioning receiver; compact with integrated antenna
Hybrid GPS / Galileo receiver compact with integrated antenna and pads for surface mount
Generic Arduino Ethernet Shield based on Wiznet W5100 chip. Ready to work with Arduino UNO or MEGA2560 board.
WiFi Module ESP8266 with shielding and ceramic antenna (optional external antenna)
NodeMCU is an open source card that helps to make rapid prototypes with a few lines of code in LUA language. Currently one of the most populard platforms for the Internet of things. Also compatible with Arduino IDE!
Nordic Semiconductor's nRF905 chip based module
ESP8266 SoC WiFi module