Your microwave must have a rotating tray. If it does not rotate hot spots can occur resulting in overheating or fire. It must be able to fit the Weighted Wrap comfortably without touching the tops or side so that it can rotate freely. Minimum size for the interior of the microwave is 30cm x 30cm and 14cm in height.Unfortunately, our Weighted Wraps are not compatible with dual function / built in / convection microwaves. These devices often contain metal grills and lack rotating trays. Contact with metal, or close proximity while microwaving will result in damage to the wrap or fire.Never use with incompatible microwaves.