This thermostat is the replacement for the RDE20.1 which was discontinued in August 2013. It will use the same remote probe sensor.

Siemens RDE 100.1 wall mounted thermostat. The thermostat can be configured to sense either air temperature or remote probe temperature sensor which is ideal for under floor heating. (Probe not included but can be supplied separated for $18) This temperature controller allows you to set the ideal room temperature for any time you want it. The settings are totally variable, set to your specific needs or use the factory settings already programmed. Temperature range is 5 to 35 degrees Celsius. Can switch loads up to 230volts 5amps single pole. Can be used for cooling be connecting the reverse bias contacts. Fits into a standard vertical wall flush box. If you require large quantities ask me for a deal. DIY under tile heating kits can be supplied. Ask a question with area to be heated and we will offer you a cost.

See link below for operating instructions and look at this fine instrument. http://www.youtube.com/watch?v=Z7NSZaTW90A