Balancer spiral

This is a very old non-tilt window spiral balance. We may be able to identify it, but I'll need you to remove one from the window entirely so that we can get a better look at it. We'll need a clear picture of the bottom end of the spiral, including the bracket it uses to connect to the sash. We'll also need the exact length of the outer tube and the exact length of the inside spiral rod. Finally, we'll need the weight of the sash. It may not be possible to remove your sash from the window, but if you place a scale on the sill and lower the sash on top of it, then we can at least get a good idea of what we're working with.