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