The tiler breaks tiles to size with these tile cutting pliers. First, you draw a straight line where you want to break off the tile and then you cut the glaze layer with a tile cutter.
Finally, hold the tile on the line with the pliers and squeeze the pliers closed. The tile breaks off exactly at that place. The jaws are adapted to the purpose: the lower jaw is narrow and exerts a lot of pressure in one place to break the tile. The upper jaw is wide and winged and stops the tile. The wings are slightly bent so that the pressure is further increased. There is also a wheel on the lower jaw to roll a little further each time when the tile is broken.