Viagrow Four Tray Heat Mat 48" X 20.5" with Digital Heat Mat Thermostat. The ViagrowTM Seedling Heat Mat Thermostat can be used to regulate the temperature range of your The ViagrowTM Seedling Heat Mat between 40 & 108F (5 to 24C) The ViagrowTM Seedling Heat Mat speeds germination and encourages strong root growth The ViagrowTM Seedling Heat Mat fits snugly under four standard size seed trays The ViagrowTM Seedling Heat Mat Thermostat has a 6 foot power cord The ViagrowTM Seedling Heat Mat Thermostat has an easy to read digital temperature display that shows temperatures from 32 to 140F (0 to 60C)