I am car-sitting a vehicle that mostly sits in my garage.  I don't drive it nearly enough to keep the battery charged.  I am also convinced that Fords have a damn trickle as this car drains a battery faster than anything else I have seen [maybe not as fast as a snooty BMW].  I spent a hoop of time looking on line for a quality product.  This one was well reviewed on many forums and after going to the factory web page I was convinced.  Amazon had the BEST price period.  I ordered four to start, one for Dad [has a truck he rarely drives], one for car I "baby-sit", one of wife's Jeep it sometimes does not get driven for days which is only a concern during cold Illinois winters, and my truck which always is outside [does not fit in garage] and thought it would be a good idea on those super cold nights when I also plug in my battery blanket and oil heater.