The New York-based burger chain opened its first Los Angeles location on Tuesday. According to LAist, the new outpost will offer two new menu items exclusive to West Hollywood: The “Roadside Double” is a double Swiss cheeseburger with dijon mustard and onions, simmered in bacon and beer; and the Rainbow Connection is another variation of Shake Shack’s frozen custard using donuts and jam from two local establishments—Cofax Coffee and Sqirl. A portion of sales from the latter will go to LA PRIDE, a non-profit organization that organizes annual pride celebrations.

Considering L.A. is right in the heart of In-N-Out territory, the move is sure to strike up a battle of the burgers.

In-N-Out is a fast-food restaurant with a simple menu consisting of burgers, fries, and soda. Shake Shack is considered a “fast casual” restaurant, a concept that’s recently been increasing in popularity. It has a more extensive menu that includes hot dogs, chicken sandwiches, dessert, and even alcohol, though it’s more expensive than In-N-Out.

In-N-Out has the advantage of being more established. According to Mic, it was founded by a World War II veteran nearly 70 years ago, and there are currently over 300 locations in the western and southwestern U.S. Shake Shack was founded by restaurateur and Union Square Hospitality CEO Danny Meyer just 12 years ago.

Shake Shack has about 50 locations. The company announced a plan to expand to 450 when it went public last year, though it didn’t provide a concrete timeline. Fortune reported earlier this month that Shake Shack’s shares had fallen sharply as investors fear the chain is losing steam.