Birthday Express - Monster Jam Trucker Hats Includes (8) Paper Trucker Hats. Each hat is adjustable and measures approximately 5"x7" in size. Add matching tableware, favors, accessories, or a party kit bundle to complete your Monster Jam birthday party. Features favorite monster trucks including Grave Digger, Max-D, El Toro Loco, Monster Mutt, and Mohawk Warrior.