The Billy Oh 4000 Lincoln Wooden Clear Wall Greenhouse with Opening Roof Vent is a best value greenhouse for its durable & sturdy construction. The wall is composed of high quality transparent styrene wall glazing for even lighted surroundings for the plants to grow in good health. There is an opening roof vent for the plants can take enough warmth & airing it needs. The greenhouse keeps the plants & flowers arranged properly & insulate them in times of winter or bad weather. It has many sizes to choose from & yet construction is sturdy, robust, easy to assemble & with cozy design.