spare car key

https://carkeyrepairspace.brightsora.com/posts/how-car-key-repair-can-save-you-time-and-money

It's that faded, worn key you almost forgot about, tucked away in a desk drawer or taped inside the car's owner's manual. When your primary key gets locked inside the grocery cart, dropped down a storm drain, or simply decides to stop working, this unglamorous duplicate is suddenly the most valuable thing in your pocket. It doesn't need to be shiny—it just needs to turn the ignition.