Simple to use and economical. Just add the Aroma Crystals and turn on the light - it's that simple. This lamp can also be customized with the Metal Jackets that are sold separately. There is no flame and can be used in class rooms, college dorms, nursing homes - anywhere that open flames are not allowed. Each jar of crystals contain approximately 2-3 refills. Please use with our Aroma Crystals, VOC and CARB compliant, only, replacement bulbs are available. Follow the instructions that come with the lamp to avoid overfilling. Resin & glass.