There is no lip on the bottom to prevent papers from sliding down/off if they are not clipped at the top. The sliding arm pinches the left side of documents causing the papers to slide to the right. If you only need this once and a while and for only a couple of sheets of paper it is probably sufficient. I wouln't recommend this for regular daily use.
I am on the computer all the time doing homework for school and work. Using this product has decreased my neck pain because I don't have to keep looking down and across from my computer key board.
I already have one in all metal and I went looking for the line locator. Since they are not available alone I purchased this one and I really like it. It also accommodates regular sized paper and large sized paper. You can also read through the line locator.