Channel balance replacement

Welcome to SWISCO! I have a good idea of what this is, but it's not 100%.

Unfortunately, I can tell that your ruler isn't very accurate. Let me explain: 

You're showing around 1" for the depth of the bottom attachment, but using the width of the wings as a baseline, I can tell that the 1" mark isn't accurate. The 15/16" wingspan should all but touch the 1" line, but we can see that on your ruler, it doesn't.

The balance is either Series 380, with a 1" depth, or Series 385 with a 1-3/32" depth. Measure up and see if you can tell which you need. You may need a measuring tape or protractor of some kind to get a closer measurement.

Comparison of 15-004 and 15-005

Ah, no; unfortunately, window sashes vary a lot in weight. There are sets of standard sizes, width by height, but those different standards vary from tiny to large, so no balance can cover more than a small range. It's best to weigh the sash and choose the closest option for your window.