The IMP52D has been disappointing. It charges very fast; it supplies a lot of current. The charge delivered is only about 50%-60% of rated capacity. I have owned batteries that delivered as much or more than their rated capacity. The form factor is very good. It fits anywhere in my ScottEvest jackets, and I do like the LED light and the laser. The ergonomics are very good. I use the laser often in presentations. Unfortunately, this "5200" mAh battery is actually a "2600" mAh battery. For me, that is unacceptable. The core capability of this is as a battery, and it does not perform anywhere near its stated capacity.