Offer only valid for qualifying orders through the Shack Mobile App or via shakeshack.com at participating Shake Shack locations (excluding airports, stadiums, arenas, travel plazas, and museums). Offer excludes any applicable taxes or fees, including delivery fees, service fees, and paid add-ons. Offer excludes all paid add-ons such as whipped cream, malt, bacon, and cheese sauce. Offer only applies to classic crinkle cuts and excludes all limited time offering shakes