Flatbed scanners are able to scan anything that can be placed against the glass. You need a scanner with a flatbed for photos or other easily damaged originals, bound material, and 3D objects. Usually flexible lid makes it possible to scan thick documents or even books.
The width represents the horizontal dimension of the product. We consider a smaller width better because it assures easy maneuverability.
We consider a thinner chassis better because it makes the product more compact and portable. Thinness is a feature highlighted by many manufacturers of mobile devices, but it is essential for a wide range of products.
The height represents the vertical dimension of the product. We consider a smaller height better because it assures easy maneuverability.