Need to replace window balance on 3 windows

I am unable to find the maker of this window and I'm having trouble finding replacement parts. They are the original windows from a 2002 build. I cannot afford to replace the whole window. The window shown still works, I have 3 other windows that have the exact same window balance that need to be replaced. The bottom piece is shaped like a "T" and when twisted can be removed, it measures 1 1/4" wide when removed . From my research they are " bait and tackle" type balance's. They don't have a metal "U" shaped channel like all the rest I see online. The gap is about 5/8" wide. The channel is 51" tall. Please help lol