I have a Motorola E815 phone approaching 4 years old and the original battery was only lasting about a day. I had heard that a new battery would cost me about the re-up price for a new phone from Verizon. Since my life is quite transitional now, I really didn't know what phone I wanted or needed, hence when I found this battery for less than $10 delivered I thought it was worth the shot. I think I ordered it on Friday and it was in the mail Monday, much faster than I expected. The battery and the new back still fits within my leather case, and it gives probably four days with moderate use. More usage cuts it down, but I still get a couple of days before it needs to be recharged.