FLUE DUCT EXPANSION JOINTS STYLE 600 SLEEVE TYPE Squeare, rectangular or round shapes can be produced in almost any size. Standard constructions is "U" shape with a 9 inch face-to-face dimension, with a 3 inch flange (other face-to-face dimensions available). STYLE 600 U-TYPE Squeare, rectangular or round shapes can be produced in almost any size. Standard constructions is "U" shape with a 9 inch face-to-face dimension, with a 3 inch flange (other face-to-face dimensions available). STYLE 600 U-TYPE Squeare, rectangular or round shapes can be produced in almost any size. Standard constructions is "U" shape with a 9 inch face-to-face dimension, with a 3 inch flange (other face-to-face dimensions available). STYLE 600 U-TYPE Squeare, rectangular or round shapes can be produced in almost any size. Standard constructions is "U" shape with a 9 inch face-to-face dimension, with a 3 inch flange (other face-to-face dimensions available).