I got tired of the way my Bestem 2012 topcase always seemed to flop around. I saw a B33 topcase on sale and decided to bite the bullet. Although it's the same capacity as the Bestem 2012, it's taller and narrower. It will swallow a large full face helmet -- I have an XXL Nolan N104. It's also rock steady with the Givi Monokey rack. Very good quality, much better than the Bestem. Very good sealing and locking mechanism. more expensive, but wish I had bought it instead of wasting money by going cheap.