Bring your windows back to smooth, reliable operation with the proven performance of the WRS Caldwell Series 300. The WRS Caldwell Series 300 is a professional-grade replacement balance designed for non-tilt, side-load window systems. Using a precision spring-and-pulley mechanism, it counterbalances your window sash for smooth, controlled lifting and secure closing. Built with a 5/8″ galvanized steel channel, this balance delivers lasting strength, corrosion resistance, and dependable performance in both residential and commercial settings. Compatible with most vinyl and aluminum single- or double-hung non-tilt windows, the Series 300 is available in lengths from 8″ to 49″ and supports sash weights from 3 to 44 lbs. Each balance is sold individually and comes pre-assembled with top and bottom guides attached, ready for quick, accurate installation using standard tools. Selection Guide: Measure the metal channel length only (do not include plastic ends) Confirm 5/8″ channel depth from the spring opening to the back of the balance. Match the stamped number to your sash weight (e.g., “07-1” = 8″ length / 3–5 lbs). Replace both balances in the same window for best results.

Important Notes: The length of the balance will always be one digit higher than the stamp number on the channel. Balances 20″ or longer may require special handling due to size. If your balance does not measure an exact length, contact WRS for assistance before ordering. Accessories and hardware are sold separately.

From single home repairs to large property maintenance, the WRS Caldwell Series 300 combines durability, precision, and ease of installation—restoring window performance and reliability for years to come.