Built in memory to restore set temperature upon power outage! This package includes a digital controller & an Ultra Sleek Finnex 800 Watt Titanium Tube. The digital controller maintains water temperature within +/-2?F of the set value providing a safe, healthy and stable temperature for the tank. Automatic shut off overheat protection - when the water temperature over the high temperature alert setting value, the alarm will start beeping. The heating process will also be shut off automatically. Advanced digital heating control technology with adjustable low/high temperature alert setting. Three prongs power receptacle works with Finnex 300W, 500W & 800W heating tubes and other brand's heating elements. Please Note: Additional heating units may be required and discouraged from using in extraordinary setups (where warranty may be void) not limited to: Applications outside of standard aquarium use, basement setups, garage setups, ponds, outdoor use, greenhouses, extreme temperature conditions, etc.