Purchased this for my elderly mother who has terrible reading but it wasn't really helpful. When trying it in the store the magnification was minimal and didn't seem to make a whole lot of difference.
Even putting this sheet in a frame I found it difficult to keep an even distance from the source material I was trying to read while typing. Fortunately a pair of prescription reading glasses made the task of typing from fine print much easier.
It is difficult to read by when you are holding a book in one hand and the magnifying sheet in the other while trying to turn the pages. I wish I never bought it.