The (2 Pack) Hydrofarm Jump Start Soil 12-Foot Heating Cable with Built-In Thermostat is the perfect insulated heating cable for growers using media beds with sand or fine gravel. It gently warms the soil for fast germination and better growth. It heats 3 square feet and is flexible enough for any growing area. The built-in thermostat is constructed to maintain a temperature of 77-85 degrees Fahrenheit. It turns the cable off when the soil reaches the optimal temperature and will turn on again automatically when it’s cooled. It’s also water-resistant, so you can keep watering your beds regularly. The cable is bright orange for visibility. This heating cable can be used both indoors and outdoors, as well as in containers, cold frames, or directly in the ground.