YAMAHA Trombone Balancer While I don't have details on the weight or compatible sizes, I used to experiment with attaching these to YAMAHA and Conn trombones with braces to alter the tone and playing feel. There are almost no dents or scratches, but please understand that this is a used item. It's still in beautiful condition, so I'd like to sell it to someone who knows what it's for. I will pack it with bubble wrap before shipping. Thank you.