I can answer all but the measurement question since I don't have the case with me. I am a fairly heavy user, I have several email accounts, Facebook, random games, and some network and server monitoring utilities installed. (I'm in IT) The clip is what plugs into the USB port on the phone to charge it. I was skeptical at first but it works well. The way it works is you charge the case first, put your phone in it and plug the clip into the USB port. The case will constantly charge the phone until it runs down, then your internal phone battery takes over. I'll measure tonight and post a reply, but you might be able to get the specs from either safpwr or AT&T's website.