Pre-Assembled 985 Series Centurion constant force balance assembly with 3/4 inch thick coil spring.
The 985 series universal single coil balance with metal spring clip side locking brake fits single hung or double hung vinyl windows with standard 1-1/4 inch wide and 3/4 inch deep pocket. 
The Centurion 3/4" Constant Force balance uses interlocking coil spring balance in Singles, Doubles, Triples and Quads 

This item is discontinued and limited to existing inventory. Replace with #533051.

Application: Balance system for vinyl window 
Pocket Width: 1-1/4 inch (32mm)
Pocket Depth / Thickness: 3/4 inch (18.95mm) .746
Brake: Side Locking Spring Clip
Number of Coils: 1
Window travel: 40 inch (1016mm) 
Weight Code: See image / # stamped on Spring