Window Sash Balances
This was a double hung window repair we did where these vertical windows wouldn't stay open. The fix was to replace the block & tackle with matching balancing springs to make sure they opened properly.
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