YES 40 FS/FI Outside Glazed, Center Set Storefront Systems STOREFRONT SYSTEM Product Description The YES 40 FS (1-3/4 " x 4 " ) is a center set, flush glazed framing systems designed primarily for 1/4 " glass or infill panels 1/4 " to 3/8 " thick. The YES 40 FI (2 " x 4 " ) is a center set, flush glazed framing system developed for 1 " insulating glass and other types of infill panels of varying thicknesses. Both systems will accommodate YKK AP's hinged mullion, as well as our flexible mullion; these mullions allow more creative freedom where curves and angles become a functional part of the design. Product Options & Features n Outside Glazed n Screw Spline or Shear Block Assembly n Gasket With Stretch-Resistant Cord n Integral Entrance Door Frames n Enhanced Water Infiltration Resistance