Heated Mini-Greenhouse growing systems offer enhanced growing success by providing gentle warmth to your plants and by controlling humidity under the dome. Each system includes a UL listed waterproof heating mat (17 watt, 120 volt), a dome top (6.5" tall on the Hot House and 2" tall on the Germination Station), 11" x 22" watertight base tray, 72 cell seedling insert (1.5" square x 2.25" deep cells) and instructions with growing tips. Hot House dome has two ventilation points on the top. Heating mat is designed to reach a temperature that is 10-20° above ambient air temperature.
I bought this mostly because it was almost the same price as just the heat mat and came with trays and a lid.
I planted tomatoes and peppers and had excellent germination success. It was night and day compared to last year without a heat mat. The 72 cell tray is really wobbly, but that's not much of a problem because it comes with another tray to put under it. The lid is short, so it's really only usable for the actual germination of the seeds (maintaining nice humidity) but that's not too bad.
The heat mat is also excellent for putting under rising bread! The gentle bottom heat is perfect keeping rising bread warm in the cold winter months. I'm an avid bread baker so this was a fantastic discovery of the dual purpose of heat mats.