This Prime-Line Drapery Cord Tension Spring and Pulley is a drapery cord tension spring and pulley. Use these spring and pulleys to keep your cords in order. With the drapery pulley system installed, it is easy for one-handed operation of your shades and drapes. Each package contains 4 white plastic pieces with springs. The drapery spring system provides proper cord tension and has a universal application with most manufacturers. It is spring-loaded, so it can make minor adjustments while you pull the cord. You'll also love that this spring and pulley system comes backed by a 1-year limited warranty, delivering peace of mind.