The way the heat pack in the paragliding glove works is that the heat pack sits at the top bottom of your wrist heating both Ulnar and Radial arteries that feed blood into both Palmar Arches (Dep and Superficial). Both palmer arches feed the blood into the digital arteries that supply blood into the fingers. Heat pack heats the fingers indirectly through the blood flow. Blood flow has a considerable influence on cold/warm hands, there is a difference between having cold hands above your head or have them down your when walking. Waring up blood that flows through the palm and fingers provides warmth for the whole hand including fingers.
Here is a list of our Fly2Base Paragliding gloves.