Disposable hand warmers are a simple way to stay warm with no batteries, charging or electricity. That makes them perfect for power cuts, winter walks and cold days out.

How do they work?

Air-activated hand warmers contain a mix that includes iron powder. When you open the packet, oxygen in the air reacts with the iron and gives off heat. It is the same reaction as rusting, just much faster.

How to use them

• Open the outer packet and give the warmer a gentle shake.
• Wait a few minutes for it to heat up.
• Pop it in a pocket, glove or sock, not directly against bare skin for long periods.
• Our HotHands hand warmers give up to 10 hours of heat each.

Safety tips

• Follow the instructions on the packet.
• Do not use them while sleeping or on anyone who cannot feel heat properly.
• Keep them away from young children.

More advice: power cut checklist · what to do in a power cut · all guides.