Fred Flintstone Adult Costume - X-Large The adult Fred Flintstone costume includes the orange and black tunic and and necktie. This adult Fred Flintstone costume comes in adult sizes X-Large, Standard. This adult Fred Flintstone costume is an officially licensed The Flintstones costume. Our Flintstones costumes make great group theme costumes for Halloween! Be sure to see our Wilma Flintstone costume for her, and don't forget Betty and Barney Rubble!