* Size: It's important to choose a trombone that is the right size for the child's body. A trombone that is too big or too small will be difficult for the child to play. For a 10 year old boy, a trombone with a bell diameter of 6 1/2 inches is a good option.
* Weight: The weight of the trombone is also an important consideration. A trombone that is too heavy will be difficult for the child to hold and play. Look for a trombone that weighs around 5-6 pounds.
* Action: The action of the trombone refers to how easily the slides move. A trombone with a smooth action will be easier for the child to play.
* Sound: The sound of the trombone is also important. Look for a trombone with a clear, warm sound.
* Price: The price of a trombone can vary widely. For a 10 year old boy, a trombone in the $500-$1,000 range is a good option.
Some specific models of trombones that are good for 10 year old boys include:
* Yamaha YTB-232 Intermediate Trombone
* Bach TR502 Student Trombone
* Conn 88H Student Trombone
* King 2B Student Trombone
Be sure to take your child to a music store so that they can try out different trombones before making a purchase.