Get a jump start on the growing season with the Hot House with Seedling Heat Mat. It is well known that seeds will often germinate much more easily when provided with temperatures 10°F-20°F above room temperature. Get started quickly with your own growing media and plugs or purchase them separately for a complete system setup. The Seedling Heat Mat is UL-listed and provides gentle heat that will never damage roots. Includes base tray, 72-cell insert, vented dome, and heat mat. Full instructions are printed right on the mat. Features : 7. 5" humidity dome with three adjustable vents, Increases germination success, Better humidity control for optimum growth, 17 watts, 120 Volt heat mat, 11" x 22" watertight base tray, 72-cell seedling insert, Instructions with growing tips.