Hello there, I have the battery incl. tool and description bought because I thought for under 20 do you enable definitely try. And I have to say with the instructions and a youtube video it must be changed without problems feasible the battery. One should, of course, a little bit of understanding of matter ...;) Although the battery was 2012 but still brand new and uncharged ... have the charge cycles specially tested. Thus my Iphone 4S hällt now something more than a day ... comes naturally to the use. So I can only recommend the product. (PS: plastic lever for removing the batteries are very weak and unfortunately broken .... have me then helped out with a small Schraubenuzieher..) LG Adrian