Cortizo Aluminium Bifold Cills & Thresholds OPEN OUT CILLS & THRESHOLDS FULL FRAME THRESHOLD & 180MM CILL FULL FRAME THRESHOLD & 150MM CILL FULL FRAME THRESHOLD & 85MM CILL FULL FRAME THRESHOLD, NO CILL LOW FRAME THRESHOLD & 180MM CILL LOW FRAME THRESHOLD & 150MM CILL LOW FRAME THRESHOLD & 90MM CILL LOW FRAME THRESHOLD, NO CILL OPEN IN CILLS & THRESHOLDS FULL FRAME THRESHOLD & 180MM CILL LOW FRAME THRESHOLD & 180MM CILL FULL FRAME THRESHOLD & 150MM CILL LOW FRAME THRESHOLD & 150MM CILL FULL FRAME THRESHOLD & 85MM CILL LOW FRAME THRESHOLD & 85MM CILL FULL FRAME THRESHOLD NO CILL LOW FRAME THRESHOLD & NO CILL FRAME PROFILE Bifold Top Frame With 38mm Trickle Vent Add On