Matthews Apple Boxes are one of the most ubiquitous and useful pieces of equipment on a film set. They are used for anything that needs to be propped up or supported temporarily. They can be used to prop up furniture and light stands, for leveling camera dolly track, or to provide temporary seats, workbenches, or stepladders.
You can nail wall plates to them to hold low angle lighting fixtures and a multitude of other purposes. Matthews Apple Boxes are constructed of industrial grade plywood.
Often the need arises to make an actor appear taller, either because of their height, or to fit with the composition of a particular shot. In this use apple boxes are jokingly referred to as "man makers".
Did You Know...?
Often when a grip is placing an apple box others are lifting something heavy to put on top of it, thus arose the need for terms describing what position the apple box should be placed in (i.e., which side of the apple box should be placed face down). It is rare that these terms are used for anything other than the "full apple" size.
New York: Positioned so the apple box is tallest, like the tall buildings in New York, 20" high.
Texas/Chicago: Positioned so the apple box is resting on its longest narrow side, 12" high.
LA: Positioned so the apple box is flattest, 8" high.