These inserts are designed for use in Thrue holes, which allows for rapid and accurate alignment prior to installation. With the use of high-frequency vibrations generating frictional heat at the metal to plastic interface, the plastic melts slightly and flows into the knurled serrations, barbs and undercuts. The molten plastic will then resolidify leaving the insert securely fit in place. Ultrasonic installations of inserts offer higher torsional and pullout properties than cold press-fit methods.