We're looking for a big old fashioned one. Probably rusty like the handle.
6 seconds sound clip from the Harry Potter and the Sorcerer's Stone movie soundboard.
You can hear this line at 02:05:29 in the Blu-ray version of the movie.
Quote context
[...]
- Strange.
- What're we going to do? There must be a thousand keys up there.
- We're looking for a big old fashioned one. Probably rusty like the handle.
- There! I see it! The one with the broken wing.
- Oh, go on, Harry! If Snape could catch it on that old broomstick, you can.
[...]