Root Radiance seedling heat mat warms root area up to 20 degrees over ambient temperature, improving the germination process and overall success of seedlings and cuttings. Durable, portable and water resistant, root radiance is ideal for greenhouses, nurseries, and indoor gardens. This new series features a "Master Mat" with Add-On mats sold separately. These new heat mats are daisy chain capable, and each Master Mat can handle up to 3 Add-Ons. Also, each of these extra-large Heat Mats can accommodate up to (5) 10"x20"