Febreze PLUG cleans away odors instead of simply covering them up. It cleans away bad smells for 1,200 hours (50 days) with just one pluggable refill (on low setting). Simply plug into any outlet to freshen a room. Proprietary, ramped heating technology prevents fading over the life cycle of the refill (sold separately). Febreze PLUG air freshener refills are compatible with both the classic and the later-model Febreze plug warmer. Dual Chamber holds complementary perfumes to combat the "nose-blind" effect over time. Micro-chip in the plug-in oil warmer allows alternation between the wick for the release of complementary perfume. Intensity control includes three settings (Low, Medium, High). End-of-life light notifies you when your refill is running low.