The two sandwiches are essentially the same save for one comes with a crispy-fried chicken filet and the other comes with a grilled beef patty. Beyond that, the they both includes lettuce, tomato, bacon, natural Swiss cheese, and Sonic Signature Sauce (a blend of honey mustard and barbecue), on a King's Hawaiian bun.
Both carry a suggested price of $4.99 (varying with location).
Photo via Sonic.