Hello there!
It looks like you have a tilt window which means you want either the 3/8" diameter Series 900 or 5/8" diameter Series 600. You will have to measure the outer tube of your old balance to determine the best match.
We should be able to help with the pivot shoe though I'll need more information. Can you remove it from the window and show us a photo along with the written-out thickness and width dimensions?
Thanks for the additional information! This is a huge help. Our 15-046 measures 1/2" thick and 1-1/4" wide. Take a look at the specifications below and see what you think.
