Red Robin is offering fans a chance to get burgers with an unlimited side of fries for $20.

The burger chain has launched its Bottomless Burger Pass. Customers who purchase the $20 pass will receive a black-and-gold card in the mail that grants them a burger and a bottomless side of fries every day in May. The promotion is now available for purchase at RedRobin.com/National-Burger-Month. The offer is available for a limited time.

Later this month, the burger chain will launch a new summer menu with a barbeque burger and peach berry lemonade.

Red Robin considering closing dozens of restaurants

On an earnings call in March, Red Robin CEO G.J. Hart said that the burger chain is evaluating about 70 underperforming locations.

“We believe the expected closure of a majority of these restaurants will allow the strength of our remaining portfolio to become clear over time and free cash that we expect to reinvest in the business,” Hart said.