National Detroit is one of the best tools in the world.  They invented almost all of the popular sanding tools in use today.  If you are a professional, they are the brand of choice for high use situations. All National Detroit tools come with a manufacturers 1 year warrantee.

The purpose of an air file is to save time.  It can take up to 75% lless time to do work on long straight areas with this tool, than with a DA sander.  It also helps to keep the work straight and flat.

The National Detroit air file (also called a longboard), is unique.  Unlike most air files from other manufacturers, which just go back and forth, this tools is also a random orbital sander.  This gives you the best of both words.  There is a better finish because there are less paterns.

There are times when a longboard is just too large for the area you are working on.  That is why there is a mini, or short board.  This gives you the ability to get into the tighter areas, and still keep them straight.  This tool is also dual action.  It comes stardard with a sticky pad (for sticky paper that usually comes in a roll so that you can cut it to size).