What Our Gearhead(R) Experts Are Saying:"I swapped in the VST Termocell Winter Harness before a cold-weather ski race, and it solved the frozen tube problem I had been dealing with all season. It uses your own body heat to keep the hydration system flowing, which is a genuinely smart solution that works without any batteries or extra gear."A frozen hydration tube at the wrong moment in a winter race or a long cold-weather effort is not just an inconvenience; it is a real performance problem. The USWE VST Termocell Winter Harness is designed to prevent exactly that, channeling your own body heat to keep the hydration system in your VST pack from freezing in sub-zero conditions. It is a simple, smart upgrade that extends the usability of your VST pack well into the coldest months without adding complexity or weight to your setup.