My riding partner has this light so I can see the distance that it is useful. It stays charged for several rides at low blink. Quite impressive. Easy to charge. I have a charging station with 10 USB holes that is perfect for all our lights and GPS. Knog and otherwise.
I purchased this item to replace a competitors rear light as the rechargeable battery was not holding charge. I was taken by the run time advertised for this item and after use I am disappointed in the actual time the charge lasts. I have tried several modes and seemingly cannot get more than 2.5 hours. I personally consider the engineering/design to be rather strange. When placed in a USB slot (the only means of charging) the indicator light is on the bottom and facing the computer, requiring one to either contort your neck and head or use a mirror to determine if the light has gone from red to green. Knog needs to seriously re-engineer this product.