12" Vacuum Chamber Digital Heat PadChamber NOT Included, Sold Separately. Heat Pad must fit correct size of the chamber! Fits a 5 Gallon Chamber This Digital Heat Pad will adhere to the bottom of a chamber vessel with a peel and stick backing. This unit will hold a temperature within a degree to the set temperature (dependent on the environment and air movement). The temperature offset must be found to set the controller accurately. (See Operation instructions in the operation manual)