It's an old photographic joke - the collapsible bottles look like concertinas. No end of darkroom workers have squeezed them while dancing around in the dark whistling Lady Of Spain. Their wives and children wince but there is nothing that can be done about it.
We discovered a mother lode of them in the back shelves of the storage area recently. Buy a set to put your darkroom chemistry in - If you've mixed up a big batch of developer and want to use it in small increments you can squeeze the bottle down to reduce the amount of trapped air and thus retard oxidation of the mix.
They're only $ 7.50 so there must be a lot more things you can think to do with them. Hornpipes....
