Webasto 5013874A SmarTemp Control 3.0BT Bluetooth enabled Timer for Air and Coolant Heaters. This is the control only. Air Top 2000 STC with rheostat controller – you’ll need adapter harness 5013929B EVO 40 with rheostat controller – you’ll need adapter harness 5013930A Air Top 2000 STC OR EVO 40 with an older, 2.0 version of the SmarTemp controller – you’ll need adapter harness 5013931A For added flexibility with controller mounting location, add extension harness RPC1010001. If you are upgrading an existing controller as listed above, this harness will be in addition to the required adapter harness. The Webasto SmarTemp Control 3.0BT provides the following benefits to your Webasto air heating system: North America kit compatibility only, will not work with imported European heaters Remote Control via Bluetooth paired device Precision bunk temperature management Easy to set time and day of the week One touch instant heater start/stop Easy to program air heater start times Easy to read LCD screen displays mode, current temperature and set temperature Preventive maintenance reminder and low voltage disconnect alert English, French, Spanish Fahrenheit or Celsius temperature display Works in 12v or 24v systems **Not compatible with AT2000 Models prior to STC **Not compatible with 4kw models prior to EVO40/55