Currently one of the most common window balances, block and tackle window balance systems includes a combination of two or more pulleys, a cord, and a spring. The pulleys are grouped as the “block” to reduce the load the homeowner feels. In addition, as the cord (or “tackle”) is pulled by the movement of the sash it stretches or compresses the springs, which are weighted to match the sash weight. The pulleys and springs assist with opening and closing the window. Block and tackle balances are selected based on the length of the metal channel and the stamp. Don't forget to check out our blog to learn how to properly measure block and tackle window balances, learn what your balance stamp means, and learn how to install your block and tackle window balance. Browse block and tackle window balances, parts, and accessories. If you need help finding the correct block and tackle window balance, you can contact us, chat with us, or give us a call at 1-800-842-0974 and we'll help you find your correct replacement block and tackle window balance.