 The pole is marked for the heights from (usually) the floor platform of a building for dimensions such as window sill heights, window top heights (or headers), exterior door heights (or headers), interior door heights, wall gas jet heights (for gas lamps) and the level of the next storey joists.It makes for quick, repeatable measurements without the need of otherwise calibrated measuring devices or workers skilled in using them.Craftsmen use them to mark clapboard and brick courses so that, for example, a course ends neatly below a window sill or at a door's architrave.