These reusable hand warmers offer instant heat for cold winter days and outdoor activities. Simply click the metal disk and massage the gel pad to activate, and the gel will crystallize, instantly releasing heat for up to 45 minutes. Keep them in your gloves or coat pockets for a welcome warm-up on icy days. To reuse, place the hand warmers in boiling water until the crystals dissolve, then allow them to cool completely. Each activation can emit heat up to 54 degrees Celsius. Specifications: - Weight: 118g (each) - Dimensions (packed): 90 x 90 x 15mm (each) - Activation: Click metal disc to activate - Duration: Up to 45 minutes per activation - Max temperature: 54°C (130°F) - Supplied as a twin pack - Non-toxic