Identifying numbers printed on the unit: 32-3 FA2 CMC 19
The metal channel is 33" long, the back of the channel is 1/2" wide, the open side of the channel's slot is 9/16"
One side of the window is also missing the little clip that pops out to catch the channel balance so that it can be removed. Fortunately the ends of the broken one had disintegrated enough for me to get the window apart. The two little slots where that clip normally would go are 1" apart vertically. I'll need one of those too, and I would order a few more so I have spares. I would order 4 of these channel balances since I have another window that is just like it and I want to replace them in pairs.
Best regards,
David