Sheet Metal Duct Boot; Type Register, End, Straight; Size A 12 Inch Length x 8 Inch Width; Size B 8 Inch Diameter; Material Thickness 30 Gauge; Material Galvanized Steel; Inclusions/Features Non-Crimped 2 Inch High Collar Standard, Designed Fit Pre-Stamped Boot Frame; Throat Extension Size 2.5 Inch