Up to 90 days (Per pack based on low setting). 2x refills. See the device package for additional safety information. Only for us with Air Wick Scented Oil Air Freshener products. Reckitt Benckiser will not be held responsible for damage or poor performance. Nothing but the ingredient you need. Use instructions: Remove warmer from wall outlet. Remove refill from warmer and screw cap onto empty fragrance bottle. Unscrew cap from new fragrance bottle and insert into warmer until “click” can be heard. Plug upright into outlet. Rotate plug if needed. Unit will leak if plugged in sideways or upside down. When unplugged, keep unit upright. Adjust fragrance intensity by rotating dial on top of warmer. Largest mark = max. setting.