The MONT 4 foot extension Premium kit is specifically designed for the MONT line of greenhouses.   The idea is simple, as your gardening greenhouse needs grow so can you greenhouse.  The 4 foot extension kit allows for the expansion of your greenhouse.  The MONT is proudly made in the USA from start to finish.  Each 4ft extension kit comes includes a 2ft x 2ft roof vent with automatic opener and gutters.  This is a Premium Package, which includes the MONT Greenhouse extension, and additional sections of Commercial Work Bench, Interior Shade, and Watering System.  When ordering your extension kit make sure that the color matches your existing greenhouse.  This will work with the following greenhouses: MONT-8-BK-Premium, MONT-12-BK-Premium, MONT-16-BK-Premium, MONT-20-BK-Premium, MONT-24-BK-Premium