Since their beginning in 1932, Broan has pioneered many of the product innovations now established as standards of the industry, Today, Broan carries on the commient to provide the finest products in the industry, Fan Accessories, Ducts, Transitions, Elbows, 3-1/4"" x 10"" to 6"" Round Transition, Converts 3 1/4"" x 10"" duct to 6"" round duct, SKU: ALMO2176