Color: Black Material: 100% Cotton Size: Adult Standard Fit New: Officially Licensed Batman gets salty with the periodic table, in this twist on the classic theme song. Is it any wonder that The Dark Knight would celebrate one of the more violently reactive alkali metals in his theme song? This black, standard fit shirt is made from 100% cotton. Be sure to check out our Size Chart to get an idea of the average size and dimensions of this Batman Sodium Chart NA-NA-NA-NA t-shirt style.