Its a Givi, which ive used on all my sportsbikes, box brand doesnt really matter, thou in the past ive mounted them on renntec racks but in the BMWs case, I bought a chinese pillion seat(complete with lock and key) for around £30 and drilled through the pillion seat and mounted the box base plate to that.
Someone else on the forum has done similar as well.
Its still as stable as it was up to maximum speed as well...
Thank you. I like the idea of a hard back box. Might look into these when the time/need comes.