As software goes, Sizer is one of the simplest programs I’ve ever used. Admittedly, it doesn’t really do much. But what it does do, I find quite useful.
There are many times that I need the window of a software application to be an exact size in pixels. For example, when I record tutorial movies. Sizer allows me to make any running program any size I choose. Did I mention it is freeware? It may not be something for every user, but it is handy for those of us who need it.