Review on STEELMAN TracerEAR Electronic Stethoscope Auto Diagnostics Tool, Locates Strange Vehicle Noises, Headphones And Battery Included by Tim Clark

First and foremost: Very poor soldering job. Both leads to the 3.5mm jack where broken/disconnected (technically not poor solder job, but very fine guage wire, wire broken at solder joint, on both connectors to jack and where one lead came off amplifier circuit.After re-soldering the three broken connections, then Dab of hot glue to re-enforce the connections/wire so the sheath was anchored, not just the bare wire, it does work, but unless willing to take apart and re-solder be prepared to have to return (if they will).Second while it does amplify sounds as described, the mic is to poorly isolated/insulted, and it picks up more noise, from your hands/fingers on the shaft/control unit, Pretty much if you can hear the noise WITHOUT the stethoscope, then the stethoscope is probably going to pick it up (whether or not it is ' infront' of the mic.For 15-20 dollars (if you got one that worked, or can fix yourself), it may be worth it, for $40 I would expect better sounds isolation, whether better isolated/insulated mic, to NOT pick up noise, from unit itself and/or even starting to expect low grade, but active noise cancellation.Overall it technically (once fixed) does work, so not quite worth the fight to try to return, but most certainly will not buy again, nor recommend.Ultimately resolved my need, with the old school of a cheap thrift store doctor style stethscope and a large long flat blade screwdriver for a probe (put the stethscope on the shaft and/or handle of screw driver, press blade of screwdriver firmly against spots on engine/frame and it will pick up any sounds.