BRIAN'S B Star Chest & Arm features a contoured rib design that's made of high density (HD) and low density foams with an air pillow for comfort. Air pillow extends through the collar and is lined with nylon. Same design from the Sub-Zero2 and Gnetik2 product line, the belly flap is segmented for mobility. Re-designed shoulder floaters to contour to the shoulder for more rigidity. Fully adjustable hinged arm floaters. Nylon materials on the arm exterior for durability.