Caldwell 23 3 FK stamped balancer with winged ends

Based on your photos, you have either our S380-24 or S385-24. The only difference between them is the size of the bottom fitting, which is indicated on their respective store pages. You'll need to measure your bottom fitting to confirm which one is best.

As for installation instructions, I will provide a video tutorial at the end of this post.

Comparison of the S380 and S385 balance shoes.

You can't order a balance without choosing an option. That determines the calibration of the spring.

Since your old stamp reads "23 3," you want a 2430 option. You can also weigh your sash to confirm this is correct. We have a chart on the S385-24 store page that tells you how much weight each option supports.