I tried using it with my Sansa Clip MP3 player in my Toyota MR2. The car makes a lot of noise in any case, so I'm not holding out for audio lab quality. However, the product made a quite audible (at low automobile speeds) click-click-click. I might have been able to tolerate that. However, there was also an electronic whistle increasing in frequency with the RPM of the engine. The whistle interfered excessively with the intended sound from the player. The volume of the Coby CA-747 was ok. I hadn't thought that would be an issue until I bought a comparable Maxell cassette adapter at Long's to replace the Coby CA-747. The volume with the Maxell product was very weak, and I had to turn it way up. The Maxell didn't go click-click-click, but it whistled, too. So both the Maxell and the Coby get 1 star from me. I'm trying out the offering from Philips next...