Steel Corner Mount Window Sash Tension Springs for old style rope and pulley wood windows are normally added to the bottom of window sash. 

The spring is slid up from the bottom between the window sash and frame.
Additional springs may be added to the top of sash if needed. 

Sash spring allows for repairs of broken sash cords without removing the sash.

Length: 4-7/8 Inch
Width: 3/4 Inch
Material: Spring Steel

Contents: 2 Springs and Nails

Priced and sold in pairs.