Designed to keep your brew or wine at a constant Temperate even in hot climates. An economical and space saving substitute for expensive refrigerator modifications. Fits all carboys up to 6. 5 gallons with airlock attached – fits all standard fermenters up to 8 gallons with airlocks attached. To cool just add ice packs, bottles or bags of ice, or other cold objects (use your imagination! ) and switch out as needed to keep within the target temperature range. To heat use a heating pad with thermostat control. We that our products will arrive undamaged and free of defects – covered under our 30 day hassle free replacement !