After observing how sport climbers were modifying their belay krabs with rubber bungs to prevent cross-loading with certain auto locking and assisted locking belay devices such as the Petzl Gri-Gri, DMM came up with a simple solution. The Rhino's "horn" prevents auto and assisted locking belay devices rotating off the top bar and on to the spine and so reduces the risk of cross loading.
It works best with solid metal devices such as the Gri-Gri and Mammut Smart but could be used with trad belay devices with a flexible loop though it might not stop the krab rotating so well with these.
The full cross section of the top bar means greater wear resistance, and smooth operation in guide mode usage. The horn makes identification by feel on the rear gear loop easier, and the clean nose design provides snag-free loading and unloading of ropes. The large round top bar is contrasted by I-Beam construction on the non-rope bearing surfaces reducing weight significantly.