The Riga XL (Extra Large) Greenhouses - Featuring the amazingly insulating 16 mm polycarbonate. This is the largest commercial quality hobby-kit type offered by Riga and is a fantastic choice for the truly serious gardener. The Riga Extra Large Greenhouses come standard with Triple Wall Polycarbonate with a 10 year warranty. It features 16 mm UV coated TRIPLE-wall Polycarbonate Glazing, 10 MM twin wall polycarbonate in front & back walls for extra strength. Also includes: 4 ea. large roof windows: 37.5" W x 39.5" L, large Dutch style doors: 37.5" W x 74" H, and standard automatic roof openers. The Riga XL greenhouse is attractive and beautiful to look at – and will definitely fit in well to an upscale garden setting.