Spank oozy 760 ltd vibrocore riser barthe theory behind spanks vibrocore impulse and fatigue dampening system is simple like all forms of energy the vibrational energy that is transmitted through your bars to your hands is made up of waves which can be measured in amplitude and frequency the more dense a material the higher its ability to transmit energy waves alloys have a very high density and in turn transmit vibrational energy very effectively vibrocore is a complex low density mat