High-quality stone materials. The warmers heat up very quickly. Energy efficient. Excellent heat distribution. Little oil or fat needed. Ceramic non-stick coating; Durable & lightweight shell; Anti-bacterial; Dishwasher safe; Durable, resistant, and non-stick. Due to the firing process, the outer coating is stronger and can last longer than regular coatings. Suitable for all heat sources, including induction. The lids are equipped with a steam valve for excess steam. The non-stick coating is dishwasher safe. SUITABLE FOR ALL HEAT SOURCES!