Alumax Balances

Hello! These look like fairly typical, if old-fashioned, tilt window spiral balances. My recommendation is ether our 3/8" diameter Series 900 or 9/16" diameter Series 600. These have metal tubes instead of plastic but they will still work the same way. You won't notice a difference after they're installed.

Your next step should be to measure the diameter of the outer white tube to verify which of these two options is the better fit.