Felt lucky to get one of these as have been hard to snag. Received early in January, packaged well and great communications from Lion during order and shipping. Heater strip easy to apply, instructions ok. For me, applying on competitive mini lithium battery, found terminal ends pretty light and terminal rings to small for my 8mm battery terminal bolt. Just replaced ring terminals with bigger, heavier ring ends.
Not scientific test but put battery with warmer and insulated bag outside on concrete with temp at 19•F. Put a remote temp sender unit in bag to monitor temp change and put heavy towel over bag. Let drift down to 40•F and then turned on warmer. Temp in bag immediately started climbing and stabilized at 50 to 51•F. Then put battery warmer, bag and temp sender in a perfect sized styrofoam cooler and covered that with a heavy towel. Same process but then held at 54 to 55•F. Believe this will work fine and help manage our cold weather charging restrictions.