The Compact 'HI' model of the MB5 is specifically for Yamaha horns (or horns with a Yamaha smaller ring set). The taller bell flare due to the smaller diameter ring won't fit in the standard MB sized cases (except for the MB1).
All other horns will fit in this model as well.
Backpack straps included.
When people say not to settle for knock-offs for a good horn case, please listen to them. This case is designed brilliantly and hits the marks on form, fit, and finish. Every detail is carefully thought out and executed in a protective and stylish package. It's hard to believe protection like this case provides can be offered in such a compact form factor. Ample storage fits my two mutes, accessories in the included zip-up pouch, two mouthpieces in the included velcro close case, and a tuner in the remaining storage slot. And this doesn't include the zippered outside pocket and music storage. I have a Yamaha triple, and the body and bell fit perfectly as advertised without any worries of the taller flare being compromised. Fiberglass shell underneath the well padded interior offer rigid defense against bumps and bruises, while gently immobilizing the precious cargo inside. Believe me, I've tried a number of cheaper cases and none hold a candle to the quality of a genuine Marcus Bonna case. You won't be disappointed!