DS18B20 Water-Proof Temperature Sensor Probe

This is a sealed (waterproof) and pre-wired digital temperature probe, based on DS18B20, 1-wire digital temperature sensor from Maxim IC, providing data in degree Centigrade with 9 to12 bit precision over the range of operation (-55C to 125C). This probe lets you precisely measure temperatures in wet environments with a simple 1-Wire interface. Because they are digital, you don't get any signal degradation even over long distances!
Each DS18B20 IC has been assigned unique 64-Bit Serial Number at the time of manufacturing - allowing for a large number of such sensors to be used on one data bus. Thus a single microcontroller can receive data from many DS18B20s distributed over a large area. This feature could be handy in various data-logging and temperature control applications.   
DS18B20 has an alarm function which can be used for setting user-programmable upper and lower trigger points. It has 1-Wire® bus communication feature, requiring only one data line (and ground) for communication with microprocessor. The DS18B20 has accuracy of ±0.5°C over the range of -10°C to +85°C.
The only downside is they use the Dallas 1-Wire protocol, which is somewhat complex, and requires a bunch of code to parse out the communication. When using with microcontroller put a 4.7k resistor to sensing pin, which is required as a pullup from the DATA to VCC line.

Cable specs:

•  Stainless steel tube 6mm diameter by 30mm long
•  Uses DS18B20 temperature sensor
• Cable is 4mm diameter and 1 Meter Long
• Three wires - Red connects to 3-5V, Black connects to ground and White is data.

DS18B20 Sensor Technical specs:

•  Usable temperature range: -55 to 125°C (-67°F to +257°F)
• 9 to 12 bit selectable resolution
• Uses 1-Wire interface- requires only one digital pin for communication
•  Unique 64 bit ID burned into chip
•  Multiple sensors can share one pin
•  ±0.5°C Accuracy from -10°C to +85°C
• Temperature-limit alarm system
• Query time is less than 750ms
• Usable with 3.0V to 5.5V power/data

  Datasheet:

        http://www.adafruit.com/datasheets/DS18B20.pdf