If they are the brass wire covered jobs, they are to remove lead from shotgun bores.
Since we now use one piece wads, and have better cleaning supplies, they are in less demand, except for us old folks.
I bought a few of these from an estate sale of Tomlinson's son. From what I've read they were first made for Tomlinson by the Union Hardware Co. in the early 1900's. The ones I have were made by Outers after WWII. They are quite well made. Aluminum plates, carbon steel springs, stainless steel body and end caps, and brass screens. Click on the link and see what Brownells wants for a new one!!
PS. If they have sitting around for a while, better take them apart and oil the flat steel springs.