What is this filter used for?

[cfd577]

I recently purchased a lot of equipment from someone getting out of home brewing In a box of random parts were these filters. Any idea what they should be used for? Part of the purchase was a single tier system with rims. The only thing I can think they may be used for is a filter for the rims system. Not sure why the different sizes then though. Thanks for your help.

 

[swackattack]

Keeping hair out of a sink

 

[TheCanisDirus]

^^^ beaten lol

 

[BBBF]

Why have I not thought about putting one of these in my bottom drain keggle?