What block and tackle is this

Question

My windows  are about 24 years old, single hung, none stay open, would like to replace with the right block and tackle if possible. Also how do you measure for block and tackle to get the proper size, as these don't have a channel.

Casey · Accepted Answer

Hello,

You have old-style rod balances that are no longer made. However, you can use the Series 795 channel balances as long as the spring diameter measures 1/2" on your assembly. The video below will go over everything you'll need to know. Thanks for posting!