The Leaktronics Premium Yellow Line Series Mics are an enhancement upgrade to the standard mic provided in our kits. The LeakTronics Premium Yellow Line Series Pipe Mics have an increased sensitivity, making honing in on the sound of leaks more accurate. The cables are also an increased length, now 25 feet. The Yellow Line Series Mics are also able to pick up a wider range of frequencies. They are simply superior to any current technology on the market!