inputs.text: better units cheaper - important not units created equally different vendors looks like identical itehems may differ substantially quality first one bought popular online auction website shipped china worked great using sd card input tried hook usb thumb drive extra voltage pull thumb drive fried circuitry inside needless say came amazon replacehement found unit assuming manufacturer products look identical pictures different models unit zero bass response cell phone bass unit paired 500w car audio systehem unit starts track 001 every time loses power unit screen 4 digit led type display 80s technology backlit lamp bleeds light display comparison unit purchased different vendor acceptable although meager bass response track mehemory passivematrix lcd display coolwhite backlight clearly shows fm frequency directory scrolls track file name first digits filename anywhow recommend looking elsewhere unit like good ones available less 10 free shipping look around bit good luck