A serif subclass characterized by heavy, block-like serifs of roughly the same thickness as the main strokes, with little or no bracketing. Slab serifs emerged during the Industrial Revolution as display faces designed to command attention in advertising posters and handbills. Their uniform stroke weight and squared terminals give them a bold, mechanical presence that distinguishes them sharply from the tapered serifs of Old Style Serif and Transitional Serif designs. Generally unsuitable for extended body text, they are most effective at large display sizes.