What is the difference between 15-195 and 15-195B

Thanks for getting back to us! This is an older style that's not made anymore. Like you mentioned, you will need an all new balance. The good news is, our Series 795 should work great as a replacement. That valley you mentioned was actually phased out by the manufacturer because they didn't think it was a necessary design feature. I know what you mean about the pivot bars getting in the way when installing the sash, but the only way it affects installation is that you have to put the sash in at a bit more of an angle. Otherwise it works the same way.

The only other detail to take note of is that our Series 795 installs at the top using a screw tab. Yours might use a hook, but I'm not sure. If that's the case, let me know. It would have to be specially made.