The Handwarmer Fuel Rods are compatible with most charcoal handwarmers Providing up to six hours of warmth the handwarmers are perfect for keeping your hands warm on cold frosty mornings 2014/15 staff product test These rods work well They need about 1cm of the tip to be glowing which only takes a minute or two of blowing after lighting the tip with a lighter Once this has been done they will stay lit for 5-7 hours in the hand warmer case