Featuring rust-resistant heavy-duty aluminum frames and a SmartLock connector system, these all-climate Palram Snap Grow Hobby Silver Greenhouses assemble quickly with minimal hardware. Clear SnapGlas greenhouse panels lock into place easily and provide visibility for tracking plant growth. Pre-assembled door(s) offers easy access and ventilation. Pre-assembled vent windows with weather stripping for easy setup. Greenhouses and extension kits include a galvanized-steel base kit and rain gutters that run along both sides of the greenhouse. Extension Kits are made with the same durable craftsmanship. The 4L x 6W Extension Kit for the 8L x 6W Greenhouse and 4L x 8W Extension Kit for the 8L x 8W Greenhouse allow you to add an additional 4 ft. for more growing room. Each kit includes one adjustable roof vent for additional ventilation. Available: 12L x 6W 16L x 6W 8L x 6W 12L x 8W 16L x 8W 20L x 8W 8L x 8W Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Greenhouses.