I don't need frequent breaks in my workday to warm up my hands now that I have these nice electric hand warmers. I can't stress enough how much more my production is in this frigid weather since i can work through without those breaks. One of the most appreciated buys of the year! Super simple to use and with my power bank it gets me through a 10 hour day with warm hands. By using this device I am also getting way less cold weather damage to my fingers - those finger tip painful skin splits are not happening! I use the flashlight and during lunch break lay the device on the back of my neck using the heat with vibration mode.