25" spiral balance, 9/16" diameter gray plastic tube with white bearing, quantity is two

Thanks for your post! The S500-25 should work to replace your balance. It has a 5/8" diameter, which is considered 9/16" in the trade. You'll likely need the red tip option. A pair of these will support a sash weighing 7 to 29lbs.

You'll need the 17-012 Bracket for the bottom clip.

Additional dimensions for 17-012

Dimensions for 17-012