WRS Caldwell Series 300 Block & Tackle Window Balance - 5/8" Channel, 27" Length, Stamp 26-2 (9-13 Lbs), Non-Tilt Side-Load Replacement Hardware -
These window blocks are easy to install, fit perfectly, and are of good quality. They help in fixing window problems and are a cost-effective solution. However, some users experienced issues with the hook and pieces, and the windows sagging after installation.