Dimensions: 4W x 6H ft.Commercial-grade aluminum and polycarbonateElectrostatically charged black painted finishSpring-loaded locking doorsMade in the USA. The Riverstone Industries Monticello Hinged Greenhouse Doors let you grow your greenhouse. This extension allows you to add an additional dual-hinged door to the rear end of your Monticello greenhouse. The doors are the same premium-quality ones used in the original design. Retrofitting these doors takes approximately four hours. About RiverstoneWorking from the motto Green Products for a Brighter Future Riverstone Industries was born from the desire to bring products that were good for the environment to the mass markets. Their mission is to solve problems through innovation and function while keeping value and customer service at the forefront of their thinking. Riverstone prides themselves on offering innovative improvements to existing products currently found in the marketplace. Riverstone has maintained a position of outstanding quality and customer satisfaction through the years ensuring their growth and expanding their current stature.