Ferrite rod. To use the iM3 42-12 ultrasonic cleaner tip wear guide, use the 42-12 ultrasonic cleaner tip wear guide to check if your ultrasonic cleaner tip needs replacement. 1. Tip wear will significantly reduce the cleaner's performance, as it will affect the ultrasonic frequency. 2. The ferrite rod must be tight – a loose or broken rod will result in weak or no vibration. 3. Using a properly functioning tip at a power setting of 3-4 lights will produce a cooling mist around the tip.