S380 vs S385 Window Balance: How to Tell the Difference
The main difference between an S380-compatible and S385-compatible channel balance is the depth of the bottom shoe.
S380-compatible: approximately 1" shoe depth
S385-compatible: approximately 1-3/32" shoe depth
S380 vs S385 comparison
These two 1/2-inch non-tilt channel-balance configurations can look almost identical. They are commonly sold as Series 380-compatible and Series 385-compatible configurations. The shoe depth is the useful separating measurement.
| Likely configuration | Bottom shoe depth | What to verify |
|---|---|---|
| S380-compatible | About 1" | Metal length, fittings, and stamp |
| S385-compatible | About 1-3/32" | Metal length, fittings, and stamp |
How to measure bottom shoe depth
Measure the bottom shoe from heel to toe, or front to back, with the shoe removed. Do not use the stamp as a substitute for this measurement.
Why the stamp is not enough
A stamp such as 25 3 JR CALDWELL helps determine spring strength or calibration. It does not by itself identify the exact balance series. Two balances can share a stamp while using different fittings or shoe depths.
Example identification workflow
- Confirm the window is non-tilt and the channel is nominally 1/2 inch.
- Compare top and bottom fitting shapes.
- Measure the shoe depth carefully.
- Record the complete stamp and metal channel length.
Common mistake: choosing S380-compatible or S385-compatible from appearance alone. A small shoe-depth difference matters.
Related guides
Use the printable shoe-depth and fitting field reference to check both ends of the removed balance.
How to measure a window channel balance · Window balance stamp codes explained
Check My Window Balance →