Teenage Mutant Ninja Turtles Letter Banner 8ft by Hallmark Marketing Corporation. $9.49. Teenage Mutant Ninja Turtles Birthday Banner is made out of plastic and is 8 feet long and 6 1/2 inches tall. Banner reads "Happy Birthday" along with fun images of our half shell heroes on either side of the banner and in the center. Includes plastic string on each end to hang from. Banner has design on one side.