Pivot bar

Thanks for writing in. This looks an older version of our Series 140 Coil Balance system. The nice thing about the Series 140 is it comes as one whole part: pivot shoe and coil springs assembled. You'll need to weigh your sash and divide that exact weight in half to confirm the proper spring weight option. For instance, if your sash weighs 20 lbs, you'd need the 140-10. The stamp on the housing might indicate you might indeed need our S140-10, which is for 10 lbs of support on each side of the sash, but I advise weighing your window sash to confirm this to be safe. 

A final issue here is the pivot bar. I am not sure if your old one is going to work with the current S140, so you'd need either our 26-398 or 26-405 as replacements, depending on which more closely matches your current pivot bar's hole spacing.