Temperature Control Waterbed Heater by Blue Magic Adjustable Temperature Dial - Lets you monitor your waterbed heater. COnvenient to use - Mounts on bed frame for easy access. Durable Performance - made with a durable metal circuit path and a premium quality vinyl for years of safety. ONLY for use on waterbeds with a rigid wood frame with a watermattress that has an 8" minimum of water. Not for use with Soft Side Waterbeds or Tube Type Waterbeds.