This is a lightweight fiberglass case for screw bell double horns made in Brazil by Marcus Bonna. The XL version of the popular MB5 case is the same size shell but the inside is laid out slightly differently.
The photos show a Hans Hoyer G10A and a Paxman Series 4. The G10A is a Geyer style instrument and the body is a larger diameter, so this is the instrument the XL case is made for. Other large body horns like the G10A include Atkinson AG2000, Louis-Durk LDx5, and to some extent the Yamaha 667, 671, 871, though the Yamahas aren't as large. Maybe Yamahas fit in the standard MB5. The photo of the two horns together shows G10A on the left, Paxman on the right. Also to note...a Conn 8D, Hans Hoyer 6802, Holton Farkas and Yamaha 668 are the same size as that Paxman, and don't need the XL case.
You can tell the XL body horns because the first slide does not hang over the edge of the body, and the bell tail brace is closer to the screw ring. The Paxman also fits, but the space is larger than it needs to be. For a normal size horn like that, the standard MB5 will fit fine and give a bit more storage.