Heat plates & bowls with minimum fuss & without cluttering up your oven. Simply heat these Plate Warmers in a microwave for 2 minutes then place on your plates to keep them hot for up to 45 minutes. Alternatively you can place a plate warmer in a bread basket to keep rolls warm. The Gel inside is hot after 45 secs but the protective cover does not transmit this unless the pad is held in your hand for about 1 minute. Once on the plates the heat is conducted to the surface of the plate to warm it. The pads can also be used from the fridge to keep drinks & food chilled. Reusable they can be washed by h&. Cotton drill. Set of 4. 18cm dia.