Gel PVC Slipper cold compress:relieve headache,fever,toothache hot compress:relieve arthritis,stomach trouble,...... materia Gel PVC Slipperhelp stimulate ... , soak it into hot water approx. 80-90 degree Celsius for around 3 minutes; for cold use, please place it in the ... freezer for half and hour before usin pvc cold and hot pack, reusable ...