Round-O 152,203,254,305,356,406,457,508......1778,1829 per project need Half round-D,large half round-HD 152,203,254,305,356,406,457,508......1473,1524 per project need 1/4 round-Q 152,203,254,305,356,406,457,508......1473,1524 per project need Ellipse-E (305,406,508,610,711,813,1640)x(1016,1524,2032,2540,3048) per project need Rectangular-S (559,610,660,711,762......3200,3404,3708)x(406,457,508......762,813) per project need Durkeesox is a professional fabric ductwork manufacturers, we provide cloth ac duct, half round duct, etc. Want to know more? Contact us.