The NEW MSpa Concept Series 4-person MONO Bubble Hot Tub from Penguin Hot Tubs combines revolutionary design and legendary performance. The super stiff DWF material and brand new all-in-one external control box offers a fresh contentment for is contemporary exterior and user-friendly experience. It is more than just a hot tub. PTC Heating Technology – Mspa has applied the PTC (Positive Temperature Coefficient) technology on all spa products. It ensures a quicker heating up and long-lasting water heat preservation effect. Features: Double Wall Fabric Drop Stitch Technology 40°C Quick Heating System PTC Safe Heating Technology Whisper Quiet Technology O3 Ozone System 118 Air Jets Massage System 3-level Adjustable Bubbling Tech Energy Saving Timer Children Safety Lock All-in one control box Antibacterial fabric Anti-icing system Specifications: Water capacity: 720 Litres Net Weight: 34.5 kg Jets: 118 Air Jets Seating: 4 person Heat increasing rate: 1.5 - 2.0°C per hour Control system: