Convert from iron to zoll [Switzerland]

Unit Definition (iron)
The iron is a traditional unit measuring the thickness of leather used in making shoes, especially the soles of the shoes. One iron is equal to 1/48 inch (0.5292 millimeter), so a sole 1/4 inch thick is described as "12 iron".

Unit Definition (zoll [Switzerland])
In Switzerland, it is now considered a metric unit equal to exactly 3 centimeters (1.1811 inches). There's no change in the plural.