The Bi-fold Patio Door from Tostem America is a hybrid system of vinyl extrusion on the interior for energy efficiency and aluminum extrusion on the exterior for strength. Incorporated into each door is a pleated, retractable insect screen. These doors come in a range of sizes and colors. The largest size available is a 12.0'w x 8.0'h, six panel fold. The Bi-fold Patio Door is currently available in Northern California.