Adjust the scent intensity to your preference with the adjustable dial. Each refill lasts up to 80 days if used 12 hours/day on setting 2. Use with Ambi Pur single chamber plug-in refills, sold separately. Also try Ambi Pur 3 Volution air fresheners to experience 3 beautiful scents that alternate every 45 minutes. Create the ambiance you desire in your home with Ambi Pur Single Chamber plug-in air fresheners. Use the electrical diffuser with Ambi Pur Single Chamber plug-in refills which are available in a bountiful range of high quality fragrances which let you & your home enjoy a true scent experience. On top of this, you can adjust the diffuser depending on the intensity of scent you desire & each refill lasts up to 80 days if used for 12 hours per day at setting 2.