This was installed by two handy men - the first they had every done.  Went very well.  This mount was chosen because of the 20  inch extension.  The wall is recessed so the TV needs to come out of that hole.  The mounting plate sets above the 23" LED TV an inch but the length of the extension makes that O.K.  I would have done this myself (68 yo female) except the handy stud finder declared the whole 3' wall was a stud!!  With much chatting the handy men were finished in 45 minutes.