【Enhanced Battery Life】Say goodbye to disposable hand warmers! OCOOPA's advanced hand warmer offers an extended 15-hour heating duration with a soothing touch. Experience rapid dual-sided warmth in just 3 seconds. Perfect for outdoor pursuits like hunting, camping, and golfing.【Intelligent Heating】Stay in charge of your warmth with smart temperature management. Choose from three adjustable levels (35°C to 55°C / 95-131°F). The high, medium, and low settings provide 8, 12, and 15 hours of heat respectively.【Durable and Safe】Diverging from conventional warmers, this model boasts a reusable Tesla-grade battery coupled with multiple safety layers. Be safeguarded against over-voltage, over-charging, over-current, and short circuits.【Extra Backup Power】More than just warming, it transforms into a power bank, charging iPhones and Android devices. Compatible with USB Type C, USB Output, and Micro-USB ports, all in a compact, travel-friendly design.【Warm Tech Gift】Elegantly packaged, the set includes the hand warmer, velvet storage pouch, silicone lanyard, USB-C cable, user manual, 12-month warranty, and 24/7 customer support. Stay warm and ready for winter's embrace!