These Window Sash Balances replace single or double hung sliding window balances. Before ordering, measure the length of the metal channel on your sash balance and check that the number stamped on the back of the metal channel match the sash balance you are ordering. Some sash balance lengths have multiple weight ratings so it is important to note the weight of the sash. Each weight listed is based on 2 balances per moveable sash. While these balances are 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. Older balances will have different spring rates than new balances and the difference may cause the window to bind in its channels making it difficult to open and close the window. Some sash balances have 'wings' on the end caps, and some do not. Balances without wings are compatible with windows that previously had 'winged' balances. Number Stamped On Balance: 3230 or 32C