Those types of hand warmers are not as good as the USB battery rechargeable packs.U mean those warmer heat packs ah? Shake and use when needed... I have them handy.. charcoal ones and what one. Sometimes its really the wind that I need to guard and also getting the balaclava for full face protection. I need a good down jacket and i learned that not the puffier it is the warmer i will feel!
Get the battery ones.