Reusable Hand Warmers. Snapping the internal starts to generate instant heat, reaching up to 130 degrees. The internal chemical reaction generates long-lasting heat. Heat when you need it fast. Stop filling up landfills with disposable hand warmers! Recharge by boiling your Pocket Warmers in water for 10 to 15 minutes. Remove and allow to cool to room temperature. Complete instructions printed on item. Made from pvc material, measuring 3.94*3.94*0inches, this custom reusable hand warmers. Usage Scenarios: Office supplies, school stationery, corporate promotions, trade show giveaways. Customization available: Print your logo or customize packaging and color schemes. Product Highlights: Portable, durable, practical for daily use.