A multiple use product, our 4” diameter semi rigid flexible ducting can be used for suspended ceilings, range hoods, exhaust and bathroom venting. Made from durable, fire resistant aluminum, and compresses from 8' to 28” long. Always check with your local codes or authority with jurisdiction before installation. Deflecto was founded on innovative, problem solving products. For over a half century, we have built a tradition of discovering and meeting needs with invention and dependable manufacturing. Today, Deflecto is the world's largest chair mat, bicycle reflector and dryer venting manufacturer and a global leader in sign and literature holders, office workspace accessories and other air distribution products.