Product Info Catalog Hardware Window Screen 18-Inch x 21-37-Inch Extension Window Screen 18-Inch x 21-37-Inch Extension Window Screen Request a Quote UPC: 77578055503 Manufacturer: Thermwell SKU: 439000 Model Number: AWS1837 18" x 21" - 37", Metal Rail Extension Window Screen, Bright Mesh Screen Wire, Extends From 21" To 37", Galvanized Rails & Varnished Wood Ends, Machine Clamped Into Metal Rails, Extra Sturdy Tenoned Corners Keep Screens Square, Zinc Plated Nails.