Bubble jet massage system (140 jet holes). No tools required for set up. Inflates in minutes using pump supplied. Heating efficiency of 1.5-2.5°C per hour up to a maximum of 40°C (104°F). Digital LED control panel. Power saving temperature sensor automatically heats water back up to set temperature if the water temperature drops by 2°C. Supplied with protective ground sheet, top cover with safety clips, 2 x filter cartridge, 1 x inflation hose, 1 x drain hose and 3 x 15cm connection hoses.