Brixwell Brixwell 96BT-2 4.5 lb Constant Force Spring 1/2 inch End Width Coiled Design for Balance Systems

Constant force spring is made from stainless steel and designed for use in spiral window balance systems. It provides steady counterbalance to window sashes, helping them lift and lower smoothly without jerking or slipping. The spring features a 1/2" width, 1" pocket size, and delivers a consistent 4.5 lbs load. Finished in gray, it fits easily into standard window balance housings. The constant force spring is an excellent device for applications where a constant load is required. The design uses a pre-stressed flat metal strip wound into a coil that forms uniform loops around itself or a drum. This allows the spring to extend and retract evenly, maintaining constant tension throughout sash movement. Used primarily in single-hung and double-hung windows, it helps control sash motion and supports reliable balance function. Its compact form suits narrow channels, making it ideal for vinyl, aluminum, or wood-framed windows. The extension-type constant force spring provides smooth sash travel and steady alignment, reducing strain on the frame and maintaining proper window operation.