Key Specifications/Special Features: Applications: Instant heat up to 55°C when activated Can be used outdoor for physiotherapy Can be reused hundreds times by following the instructions Instructions: To recharge: Wrap the hot pack in a tea towel and place in a pot of boiling water Boil for 5 to 10 minutes until all of the crystals dissolve Remove from boiling water with rounded metal or silicone tongs Do not pick up with a sharp object To activate: Gently flex the metal disc to start crystallization, when the crystallization is complete, squeeze the hot pack to make it soft and ready to use Storing: To avoid damage to the plastic pouch store in a plastic container  Perfect product for promotions, gifts, advertising, medical and baby needs