4 hours run time. Color rotating. Up to 400 sq. ft. Ultrasonic USB Oil Diffuser. NOW Solutions Ultrasonic USB Diffuser unites scientific innovation with the timeless tradition of aromatherapy to create a BPA free diffuser that uses only tap water and favorite essential oils. Instead of heat, this contemporary diffuser utilizes high frequency ultrasonic electrical vibrations to create an ultra-fine mist, which helps to maintain essential oil integrity and holistic properties. With an automatic shut-off and up to four hours of whisper-quiet operation, this attractive diffuser complements your healthy lifestyle and is ideal for home and office. Features: Extremely quiet. Easy to clean. Just add top water and essential oils. Cool steam. No heat involved/no risk of burns. Automatically shuts off. Runs up to 4 hrs. Great for home or office. 1 year warranty. Run life 5,000+ hours. Plugs into laptop or any USB port. Rotating LED lights. Specifications: Model 7523: Color: White Cover and base Misting Modes: Continuous/Off Light Modes: Color rotating/Off Run Time: Up to 4 hours Water Capacity: 70 ml./2.37 fl. oz. Coverage: Up to 400 sq. ft. Power: 5W plus negative 0.5W Dimensions: 4 inches L x 4 inches W x 5 inches H.