Double coil spring carrier support used in the Series 159 constant force balance window sash support system. Measures 1-1/4" wide x 13/16" deep. This carrier support has a closed top which will help prevent the build up dust and debris which could fall on the springs. Assemblies should be installed with a #8 pan head screw (not included). NOTE: Do not over tighten the screws as this could result in damage to the profile walls.