Thsi candle lamp's Liquid-Glow Paraffin Plastic cartridge is filled with Neo-Image's trademark Liquid Glow Paraffin Oil. It is smokeless and odorless. The cartridge fits into specified lamp designs and burns up to 45 hours. The cartridge is disposable and should not be re-filled. The space saving design provides small table footprint cost effective lighting option liquid glow cartridge contains clean and pure burning liquid paraffin.