Typically there's nothing remarkable about a fast-food business serving a hamburger. But Arby's has never sold one — until today.

The company is adding a hamburger for the first time in 60 years. Arby's will offer the $5.99 "Wagyu Steakhouse Burger" through July 31.

Fast-food restaurants use specials to attract and retain consumers. Arby's has 3,400 US locations, per Technomic. McDonald's is bigger.

McDonald's recently told investors that as costs rise, fast-food customers are becoming pickier. Fast-food establishments are fighting for customer loyalty.

Arby's may have a surprise bestseller. The company says its new burger is the "best on the market." Two years were spent creating the burger.

Wagyu, which means "Japanese cow," is rich and delicate. Arby's version is 52% American Wagyu and 48% ground beef cooked "sous vide"

Patrick Schwing, Arby's chief marketing officer, said, "Instead of manufacturing billions of substandard burgers, we're focused on high-quality meat."

American cheese, lettuce, tomato, pickles, and red onion top the Wagyu Steakhouse Burger. McDonald's is 50% smaller than Arby's since switching to fresh beef four years ago.

Arby's first-quarter sales at one-year-old restaurants rose more than 5%. Inspire "sold records" Arby's earned $4.5 billion last year, up 6%.

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