Have no marking on old coils. Cassette at top of sash housed double coils on both side. The length of the sash from the bottom of the cassette housing at the top of the sash to where the shoe with the window closed is 53". The window weighs 20lb. Wish to buy the entire balance assembly (cassette, coil, shoe) with 2 right hand and 2 left hand for 2 windows.
Thank you.