Lotte Hokaron Mini-size One-time-use Hand Warmer Kairo | 9 hrs x 10 pcs, No Self-Adhesive (Japan Import)
Open the outer pack (red colored with brand logo) and take out the white bag. Do not open the white bag, do not rub the white bag, just put it between clothes or towel, and wait for a while - it will get warmer and last for 20 hours.