Andersen 637 Narroline Sash Balancer
- Works with Perma-Shield Narroline Double-Hung Windows manufactured from 1968 to Present.
- Sash balancers are metal boxes that contain a nylon cord under tension.
- The balancer number is a code for the tension and the cord length.
- The proper balancer must be used to maintain the lower and upper sash in an open position.
- If you replace one balancer you should replace both balancers.
Note: For instructions on how to replace balancers click on the (Size Guide & Instructions) tab above.