EXACT DIMENSIONS SHOWN IN PICTURES: One (1 ea.) 27-3 or 2730 window sash balance; Overall Length Including Plastic Guides: 29 Inches; Metal Channel Length 28 Inches; Designed to support a 13 - 20 pound sash per pair. Block and tackle window balance replacement can easily be done in a few minutes per window! Cottonwood Hardware Window Parts come with the answers to your questions. We ship each window channel balance order with illustrated installation instructions and if you additional help, we will do whatever it takes to help you succeed! PLEASE LOOK CLOSELY AT THE IMAGE PROVIDED for your balance selection before finalizing your order. Identify your balances by the number stamped or printed on the window sash spring channel. Our cartridge window sash lift balances have winged end brackets, which provide stable operation and a smoother slide. If your coil spring window balance does not have these wings, our balance will still work and possibly work better than your original balance. The size of your block and tackle window balance springs are written as two numbers that represent the length of the metal channel (not including the plastic ends). This is followed by one or two numbers that represent the spring weight also known as the carrying capacity. Cottonwood Hardware window block and tackle sash balance s work in many brands of windows such as: milgard, jeld-wen, MI, Certainteed, CRL Windows, AMSCO, Jeld Wen, Alpine, Alenco, General Aluminum, BSI, and so many more! Cottonwood Hardware Block and Tackle Window Spring Balance s come with detailed installation instructions written by experts with decades of experience in the selling and installing window replacement parts. We provide you with expert tips and tricks so you will have the best outcome. Window channel balances fail over time even if the window is not used frequently and are simple to replace. DIY window springs replacement will save you hundreds of dollars per window and can be completed by almost anyone in minutes! Replacement window parts can be hard to identify but we are here to help! One (1 ea.) 27-3 or 2730 window sash balance; Overall Length Including Plastic Guides: 29 Inches; Metal Channel Length 28 Inches; Designed to support a 13 - 20 pound sash per pair. Block and tackle window balance replacement can easily be done in a few minutes per window! Cottonwood Hardware Window Parts come with the answers to your questions. We ship each window channel balance order with illustrated installation instructions and if you additional help, we will do whatever it takes to help you succeed! Identify your balances by the number stamped or printed on the window sash spring channel. Our cartridge window sash lift balances have winged end brackets, which provide stable operation and a smoother slide. If your coil spring window balance does not have these wings, our balance will still work and possibly work better than your original balance. The size of your block and tackle window balance springs are written as two numbers that represent the length of the metal channel (not including the plastic ends). This is followed by one or two numbers that represent the spring weight also known as the carrying capacity. Cottonwood Hardware window block and tackle sash balance s work in many brands of windows such as: milgard, jeld-wen, MI, Certainteed, CRL Windows, AMSCO, Jeld Wen, Alpine, Alenco, General Aluminum, BSI, and so many more! Cottonwood Hardware Block and Tackle Window Spring Balance s come with detailed installation instructions written by experts with decades of experience in the selling and installing window replacement parts. We provide you with expert tips and tricks so you will have the best outcome. Window channel balances fail over time even if the window is not used frequently and are simple to replace. DIY window springs replacement will save you hundreds of dollars per window and can be completed by almost anyone in minutes!