Question about Radio Strap

[u/Economy_Strategy_426]

Hello there folks, I’m a 15yo Explorer and was recently able to pickup a radio strap for free through my program and was just wondering one thing, what is this extra strap/ piece and what does it do, I don’t know what it’s called so I wasn’t able to research it so I turned here for help! (I’m holding it in the picture)

[u/946stockton]

Its for your car keys.