Even though L.L. Bean hired additional workers to increase production in the U.S. last year, its duck boots are still being backordered.

Customers are on a wait list for the retailer’s functional boots made with leather and rubber, according to Consumerist. Boot sales have grown from less than 100,000 annually a decade ago to a projected 600,000 this year.

The boots were originally made in 1911 to keep feet dry during hunting trips, and despite being called “ugly” and “ungainly” in recent years, demand is up again. The reason for the resurgence may just be nostalgia.

“There can be times when true classics become trendy,” Dan Hess, CEO of research company Merchant Forecast, told Consumerist. “Teenage girls in Malibu are not always going to be wearing L.L. Bean boots, but they are right now.”

 

 

 

L.L. Bean had a feeling this might happen: Last year, it hired 100 more workers to meet rising demand. But even in 2015 that wasn’t enough.

Some boot styles won’t ship until late January, Consumerist reported.