Jens Björn-Larsen (formerly of the Copenhagen Radio Philharmonic, now European Chamber Orchestra and tuba tutor in Hanover) had celebrated all his great successes and prizes on his B&S F-Tuba 3100W, and he couldn't find a comparable instrument.
Until he joined the development team at B&S himself: the basic concept was retained, but the proportions within the body were changed, all the slide bends were removed and a completely different leadpipe was fitted, with the first valve located in its centre.
In doing so, B&S surpassed Jens Björn-Larsen's original aim to be as good as the original - the new development was simply better, responded even more easily, tuned even better, and it retains the typical B&S F tuba sound, which does not try to be a C tuba sound.