Ranion Blues (currently Cronkhite) Trombone Soft Case It's large, so it's probably a case for a bass trombone. Total length: approximately 91cm, bell diameter: approximately 32cm Bell inner diameter: approximately 28cm Slide sleeve hardboard section: approximately 81cm x 33cm The sleeve itself has a little more room. It shows signs of use, but the handles and belt hardware areas are intact without fraying.