Built into both top inside faces of the sash window stiles are Sash Window Pulleys over which the cord that connects the sashes to the weights run. The weights move down as the window moves up over these sash window pulleys and vice versa. Also, because the weight for each sash is the same, the sashes are balanced and move smoothly within the tracks in which they run preventing them from sticking, and make them lightweight to operate.
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