Start your growing season early with everything you need in this kit to start your seedlings. It is proven that seeds grow better with ambient temperatures 10?F-20?F above room temperature. The Super Sprouter? Seedling Heat Mat will provide even warm temperatures for your plant starts. The 7in dome will give your plants more room to grow with humidity control. Kit includes: Super Sprouter Seedling Heat Mat 10 in x 21 in; 72 site Seed Cell Tray Insert; 10 in x 20 in Propagation Tray; Humidity controlled Super Sprouter? 7 in Propagation Dome with Vents. Clonex? Cloning Gel packet (EPA No. 79664-1). The Seedling Heat Mat is ETL listed.