I've used it only once so far; only had it for two weeks. It worked very well to distinguish locations of noises on a car with a noisy wheel bearing. You must take your time in carefully placing the wires. I bought the wired version, not the wireless, after reading reviews on the unreliability of the wireless microphones. This product was well worth the $100.
This product is AMAZING. I though that I needed a new transmission...was convinced...NOPE...was an idler pulley. BTW....I'm a very experienced mechanic and was found to be wrong....SO glad I bought this tool. Thank you for making such a great product.