The Ideal-Air Gro-Sok transition is designed for the optimal air distribution. They are lightweight, draft free, condensation resistant, machine washable and anti-microbial. They are quick and easy to install. With ?no noise technology? you will be assured of quiet operation. Ideal Air has designed the Gro-Sok using heat load and duct design technology to provide even and efficient air flow. You?re assured of getting the greatest air distribution benefits more efficiently, which reduces operating costs. Proper duct and equipment sizing is critical to a successful environment. This transition can also be used with (700854 or 700853 sold separately) to complete your full duct system.