Milliard Durable Waterproof Hydroponic Seedling Heat Mat - 20in.x20in. Milliard Seedling heat mats are MET Certified and are perfect for vegetable, herb, and flower seedlings. Warms root area 10-20 degrees to improve germination. Heat Mat created the perfect environment to increases growth success of seedlings and cuttings. Durable Waterproof Construction Includes: Heat Pad, Power Cord, Instructions