This twin pack of Summit hand warmers provide gentle and prolonged warmth for up to an impressive 16 hours. To activate a pad simply shake it in the air for 10 seconds, the pad will then heat up gradually over a few minutes. So if your out and about in the cold weather, pop these into your pockets and keep your hands nice and warm!. After use, dispose of with regular household waste. Please Note: Careful supervision required if used by children, elderly or handicapped persons.