The new design integrates a quad driver scenario into single soundbore without sacrificing frequency response. The oversized soundbore in conjunction with a belled canal tip creates a smooth, even response beyond 20khz. The single soundbore creates opportunity for small ear canals to access the response of the Engineer model (a triple soundbore design). The Engineers are now available to everyone. The new design also creates opportunity to nearly double the shell wall thickness and eleviate much of the problems caused by wax and moisture, making these truly 'Road Engineers'. designed and built for the road.