Porex #X-7642 porous cylindrical filter, closed end, pair, F/S

Description

I have no idea what these are used for, so I didn't know what category to put them in.
Here are the measurements:
Length: 4 inches
O.D.: 2.25"
I.D.: 1.75"
Lip diameter: 2"
Lip width: .5"
Note that the smaller diameter section is the open end.