The STFE100-10N is a 1-phase Active Tracking® Filter with surge protection. It continuously tracks the input AC power line responding instantly into action upon detecting extraneous high frequency noise and high voltage transients caused by everyday events such as turning on machinery, motors or equipment. It attenuates or reduces the amplitude of normal mode noise to a minimum of 90dB that occurs in a frequency range of 100kHz to 50MHz and common mode noise to a minimum of 60dB that occurs in a frequency range of 5 to 50MHz. STFE provides the industry's best IEEE C62.41 Category "A & B" Ringwave protection.