These are two-sided ladders used mostly for interior work, though they are handy too for certain exterior painting tasks. A plank placed on any rung of one and extended to that of another makes a splendid scaffold from which to paint a side wall. Four or six trestles with planks between them make up a scaffold from which a ceiling can be easily reached. Trestles are made substantially like long ladders. Two are hinged and permanently fastened together at the top. Made in lengths of 6, 7, 8, 10, 12, 14 and 16 feet long.
International Association of Master House Painters and Decorators of the United States and Canada Painting and Decorating, Working Methods30