This block and tackle balance is used on Hurd Energy Saver Consealed Jamb Liner Double Hung / Singel Hung and H3 Lines.
Also used on other manufactures windows - customer will have identify and match up picture.
To order block and tackle balance. See number stamped on side of metal
Due to the multiple sizes available these are not a stock item and have a 3 week lead time. Special order item NO returns.