well I've used clothes irons on bricks and 40watt bulbs in reflectors but here's one for all you vivarium owners in cold climaates, rock heaters! Those plug in fake rocks with flat bottoms are perfect for curing s&g joints on the back porch when the temps are in the 30's during the night. The right weight too. I knew I'd use that thing one day when the Madagascar hissing cockaroaches had to go.