What evolved from the Norman kite shield was what later became known as the medieval heater shield. As armor became more effective, shields could become smaller and more agile. The heater shields (later named this due to its resemblance to a clothes iron) were thus designed with mobility in mind. They could be used mounted or on foot and were thus incredibly versatile – both armored knights and footmen could pick up and incorporate a heater shield into their different roles. The heater shield was typically constructed from layers of thin wood in a curved triangle shape that maximized surface area (and therefore protection), covered in leather or canvas. These could be incredibly affordable, which meant they could be carried by both nobles and common soldiers. Other versions were reinforced with metal or even made of metal, though these would be by necessity more expensive. Heater shields often displayed heraldic devices, and to this day armorial bearings (ranks, achievements, and family connections) are displayed in the shape of the heater shield. It would not be a stretch to say that the heater shield is the definitive shield of the middle ages.