WINDOW HARDWARE > COUNTER BALANCES > SQUARE 1/2" CHANNEL BALANCE SIZE 40 OR D
Counter Balances are located on the left and right sides (sometimes above) of the top and bottom sash.  These balances control the weight of the sash allowing you to open and close the sash with ease.  A simple ideal can prove to be complex.  Many times these items break or wear out and need replacement.

24-30  Pound Vent Weight
This Window Channel Balance replaces single or double hung window balances with a stamped number ending with "40" or "D". Before ordering, make sure the length and stamped numbers on the channel being replaced match the length and stamped numbers listed below. While this balance is packaged and sold individually, it is our recommendation that both balances in the window be replaced at the same time. This will restore the sash to a near new condition, and prolong the life of the window.
Whenever replacing Window Channel Balances be sure to check the guides, take-out clips, sash cams and terminal clips, as age and weathering can make plastic and nylon parts brittle and worn. Even metal parts will show fatigue with constant use, so be sure to inspect them too.