FITS ALL BRANDS OF HOT TUBS UP TO 73 INCHESThis easy-to-fit Thermal Hot Tub Cover improves heat retention due to the thermal insulation making it up to 50% more energy efficient ?C saving you money! The cover is waterproof to HH 118 inches (3000 mm) . as well as UPF 50+ providing protection from extreme weather conditions.The CleverSpa Universal Thermal Cover ?C Large Square . fits all square Hot Tubs up to 73 Inches . with and without an external motor. The removable zip-off door accommodates hot tubs with external motors. The webbing straps and locking clips provide a safe and secure fit. With improved energy efficiency . using your hot tub all year round couldn’t be easier . and the thermal cover makes this more viable.*We recommend using the CleverSpa Inflatable Cover Support to stop rainwater pooling and increase Hot Tub temperature retention further.