The "v" denotes the newly added vibration function, which goes off when a call is received. This is extremely helpful when the phone is on silent and not nearby, and is a huge advantage over Bluetooth headsets without a vibration feature. The pretty strong vibration feature can be turned on or off using the volume-down button, and sometimes it is best to leave it off; it feels really strange and a bit uncomfortable to have the thing go off while it's sitting on/in your ear. It is definitely an advantage, though, and I think more headsets will follow this trend in the future due to its convenience.