2.5" x 7"
Brass, Wood & Twine
Braga

You want it strait, you want the strait line? You got it with this hand article. This tool is probably number three in terms of necessities - hammer, knife and a fio de prumo or plumb line, (plumb means "perfectly upright). We need to get something straight here - and we'll do it with this tool for verticals. Laser beams are not necessary as you don't need to point to the other side of the world. You could use a pen on a string but this is more exact, won't budge as much in windy conditions and if you are to repeat Foucault's famous experiment, it's nicer to do it in style with this our model.