A – pulley. The sash wire serves like a system that facilitates The graceful opening and shutting of one's sashes by making it possible for them to be counterbalanced in opposition to one another.  Horizontally sliding sash windows also are from time to time known as 'Yorkshire sash windows' or ‘slider’ windows. https://epcrating81233.blogspothub.com/34581059/fascination-about-sash-windows