Receiver Hitch Pin Length?

[BoredomFestival]

Sorry for an ignorant question, but I've never had a vehicle with a built-in tow hitch before...

Just got a fun logo'ed tow hitch insert to put in when I'm not towing, but the locking pin it came with is too short to fit through all the way through the hole in the LC hitch.

Any idea what length I need? Is is just a commodity part I can order from (eg) Amazon?

 

[Tripod1404]

It is rather long, about 3.5 inches. I used a 4 inch pin to have some wiggle room.