Harvest Pro? Vacuum Ovens are designed from the ground up for botanical extraction purposes. Other products on the market have been simply adapted from existing industrial and lab uses. Harvest Pro? Vacuum Ovens are built with unsurpassed uniformity and temperature control (+/- 1? F). The 3.4 cu ft oven can accommodate up to ten removable shelves each being approximately 345 sq in for a total capacity of up to 3450 sq in and uses heated walls. The 6.2 cu ft oven can accommodate four shelves each being approximately 510 sq in for a total of 2440 sq in and each self is individually heated for unprecedented uniformity and temperature control across the entire shelf. The 8.9 cu ft oven can accommodate five shelves each being approximately 606 sq in for a total of 3030 sq in and each self is individually heated for unprecedented uniformity and temperature control across the entire shelf. Our ovens warm to set temperature within 15 minutes (at ambient temperature) and do not overshoot set temperature. These commercial-grade vacuum ovens are made with solid construction and are ready to use out of the box. All models are UL Listed. See specification sheet for more detailed features and benefits.