The 11mm O-ring Injector Port tool is perfect for drilling and machining fuel rails for a 11mm O-ring Nipendenso Style Injector. This tool not only drills the through hole for flow into the rail bore but also counter bores the hole for the injector O-ring to seat as well as machines a radius at the point of entry to help prevent O-ring shear during install. Recommended speed is 300-400 rpm.