Fountain pen nibs were originally designed similarly to feather quills. Flex nibs were much more common on pens made before the 1930s. They were typically offered as an option on a manufacturer's pens so that the same model could come with a standard rigid nib or flex. Flex nibs were relatively common in Waterman pens. Model 22 was a popular choice for flex. Other brands, like Sheaffer, sold very few flex nibs. Flex nibs remained relatively common on some European pens into the 1950s, notably on Montblanc pens.