Series 303 Spiral Balance

This is the SWISCO Series 303 Spiral Balance. This sash support system is primarily used in non-tilt single-hung aluminum windows manufactured by Keller.

The tube measures 9/16" in diameter but it is considered 5/8" in the trade. The tube houses an internal spiral rod with a 15-010 bottom shoe attached. Spiral window balances come fully lubricated and ready to be charged.