DS18B20 digital temperature sensor encapsulated in a waterproof housing for external temperature sensing using the emonTx or Arduino.   

Technical 

Certified genuine maxim DS18B20 sensor 

Diameter: 6mm body (approx 6.5mm body + heat-shrink) 

Power supply range: 3.0V to 5.5V

Accuracy over the range of -10°C to +85°C: ±0.5°C.

Storage temperature range:-55°C to +125°C (-67°F to +257°F)

Cable: 1m 3-core

Includes 

1 x encapsulated DS18B20 temperature sensor 

Documentation

Datasheet 

Connecting to emonTx

emonTx temperature sensing code example 

Dallas Temperature Controll Library