The urinator must keep it warm as well. This means everyday you will be heating your sample with the urinator from 2 9 volt batteries . I'm not sure about how long it takes for it to eat through 2 9 volts but I'd guess a couple of days at work and its dead. This means you have to balance the cost $.65 handwarmers to a $4 pack of 9-volts Also, consider a way you could keep your sample warm at work without wearing it, i.e. on the heat vent, behind the exhaust of a computer, really nudged up against anything warm. Get a system of croching it in the morning then hiding it in a nearby hot spot for the afternoon, then grab it when needed.