The framework holding the glass in a window unit. A coiled spring or spiral system integrated into the jamb liners to allow double hung or single hung sashes to open and close. In double-hung windows, the rope or chain which attaches the sash to the counter balance. Available on all Pella double-hung windows. They are also applied to the open edges of a projecting window to seal the sash tightly to the frame.
Sash locks provide security and weatherability.
The track is designed to accept a specific diameter sheet metal screw to provide a secure means of fastening extrusions without the use of reinforcement. A flat board cut to fit the contour of a bow or bay window that's installed between the sills and the flat wall surface. They provide a seat or shelf space. SGCC Safety Glazing Certification Council - administers tempered glass testing and certification program. The lower the shading coefficient, the better the unit blocks solar heat.