YETI Tundra 35 Cooler Seat Cushion - Make your YETI do double duty on the boat or dock with the YETI Cooler Seat Cushion. YETI's Seat Cushion has at least 2 inches of dense foam and is made of tough, white, UV marine vinyl stitched with GORE TENARA Sewing Thread. To install, screw the included studs into the cooler lid and snap the cushion in place.