Window counterweight

I have to replace some of the counterweight hardware on a Mastic double-hung window owned by my landlords. I poked around and took the attached pictures. Please let me know which parts I should order! The counterweights are broken on both sides.
Many thanks.
Here are the photos you requested. The pivot bars are 2.5 inches long by 1/2in by 1/4, the spring mechanism bar thing is 34in long and 3/4in by 1/2in.
Many thank.

Additional photos.
To be clear, both pivot bars are also broken and need replacement. See above for dimensions.



Hello,
The channel balance shown in your photos resembles the Series 765 except that it attaches to the top of the window jamb with a screw. Unforutnately, the S765 is not designed to install that way but you can use our S770-34 balances to replace them. Just make sure to replace both sides. You'll also need to weigh your sash to determine which option you'll need. There is a chart on the product page that explains how to choose your option based on the sash weight.


If you need the pivot shoes as well, take a look and compare the specifications of the 15-135 shown below to yours.

Unforutnately, we can't determine the pivot bars that you need based on a broken part. The 15-135 pivot shoe is commonly used with the 26-021 or 26-360. We can't determine if either would work for your application but it would be a good place to start. Take a look and compare both parts shown below to an intact part from another window if possible. Thank you!

