Sunbrella Seamark is made by the same company that makes Sunbrella fabric and it is made by combining Sunbrella acrylic fabric and bonding it to a marine grade vinyl. Seamark Cadet Grey 1131 is generally used for marine toppings and boat covers but it also a popular choice for tonneau and other types of equipment covers. Sunbrella Seamark has a waterproof finish and comes with a 5 year warranty.