Window type is a Seasonshield Series 5500 spec. DH-C50/C60.
Window weight 40 lb. 30" tall.
Installed was the attached balancer stamped 2390 30. 24" long.
Recently I purchased your Sash guides # 18-161 for the above window and during installation discovered some bad channel Balancers.
Believe your S380 is the correct balancer for the replacement but not sure the removed existing balancer is the correct length for a 30" window. How should the balancer length be determined?