2 x 5.5 in Fiberboard specimen mailer 4 oz (120 ml) HDPE nm cylinder with 24-410 white polypropylene SturdeeSeal® pe foam lined cap attached. Fiberboard specimen mailers meets government regulations for mailing liquids. SturdeeSeal® pe foam lined caps have excellent sealing characteristics and offer good chemical resistance including acids, alcohols, alkalis, aqueous products, cosmetics, and household oils.