This is a lightweight fiberglass case for two trombones made by Marcus Bonna in Brazil. Bonna double trombone cases are available in three sizes, and this is the smallest size. It's designed to hold one tenor trombone and one alto trombone. From testing we find that nearly any two instruments will fit. We tested a Bach 42A tenor with Hagman rotor and a Conn 36H alto with Bb rotor, and with the right arrangement of interior pads, they fit just fine. Other similar instruments should fit equally well. The photos show a Bach 42AF tenor trombone and an S.E. Shires alto trombone.
This case has a fiberglass shell which is covered by a nylon outside cover. The cover is easily removable if cleaning, repair or replacement is necessary. There is a small amount of interior storage space plus an outside sheet music pocket. Several fabric covered foam pads can be arranged inside to customize the fit to your instruments.
This is a tough case, but Mr. Bonna recommends you consider it to be hand luggage. This may not be the best case to hand over to airline baggage handlers. (But what case is?) If you need to do that, prepare by packing well with lots of bubble wrap or extra clothing so all components fit tightly inside and won't touch each other. Baggage handler travel must be next level packing above owner-operator travel. Pack tighter than that. More.
Accessories included are: shoulder strap, backpack straps, double mouthpiece pouch, ID tag, external sheet music pocket with zipper attachment.
Bonna has a new double trombone case for a tenor and jazz trombone. It's almost the same case as this tenor-alto case; only some interior parts are different. The tenor-jazz case is useful because you can pack your tenor with F, and also either a jazz trombone or an alto trombone, the fit is not much different.