This 4-pack of Hydrofarm 12x48-Inch Propagation Mats provides bottom heat that enhances germination and rooting.This seeding and propagation mat is 48 inches long and ideal for placing 2 standard trays end-to-end. It warms the rooting area to 10-20 degrees above ambient temperature. Place it under a 4-foot fluorescent fixture and ensure the bottom surface of your trays will be heated uniformly. Daisy-chain up to 10 mats to reduce the number of power outlets being used and run multiple mats to a single outlet. The heavy-duty construction allows you to use the mat reliably for years on end. Heat is essential for effective sprouting, so grab a Hydrofarm 12x48-Inch Propagation Mat and watch your plants flourish. Hydrofarm