Use these heat mats to keep plant material at proper temperature for good rooting and good plant growth. These mats provide even, constant heat to root zone for flats and pots. Designed for use on greenhouse benches or any flat surface, they are waterproof and fully grounded against electrical shock. All sizes come with a heavy-duty 8' cord and a molded NEMA three-prong plug for 120 volt AC current. For automated control, use with RHT-4 thermostat and bench plate, both sold separately.