Dress in Shamrock Style with St. Patricks Day Costume Accessories! The St. Patricks Day arm warmers are the perfect touch of Irish pride. A simple St. Pats costume accessory that your guests will love. Two arm warmers per package. 10 3/4" long. 90% cotton, 10% spandex. Show your Shamrock Style with St. Patricks Day Costume! Dress your guests in green and gold from head to toe with our St. Patricks Day costume accessories. Greet your guests at the door with a stylish St. Patricks Day hat, or give green and gold feather boas away as a party favor at your event.