Personalized Trombone Rocks Youth T-Shirt. Trombone Rocks with three dancing rocks holding trombones is a humorous low brass design. Fun gifts for musicians at back to school, marching band, birthdays, holidays and graduation. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.