V4 DEVICE. Benefits: Safe & clean scents - Pair with premium fragrances created with ingredients that are safe and clean. Smart features - Adjust fragrance intensity, set schedules and timers, and more in the Pura app. Adaptive diffusion - Get a consistent scent experience based on the temperature in your home. Long lasting - Puralast provides a long-lasting fragrance experience of up to 120 hours. Features: Puralast creates the best scenting experience youll find anywhere. With this technology, your diffuser learns from your feedback to efficiently fill your space with your desired scent intensity for up to 120 hours per smart fragrance vial.. Automatic vial detection - Simply insert your smart fragrance vial and Pura 4 automatically detects the fragrance, creating a seamless swapping experience.. Adaptive diffusion technology reads the room's temperature and adjusts according to your preferences for a consistent, reliable scenting experience.. Smart schedules, timers and more - Adjust fragrance intensity, easily switch between fragrances, set schedules and timers, and moreall from the Pura app. Fragrances sold separately. :