But they dont sound great. I just use it indoors. No sand or rocks inside the shoes. First let me say that Ive worn these for almost 8 months, yes 8 months. I will review the quality later as I just wore them today. I know Ill be back for more as long a Mao is around. Wont be purchasing again. All info can be found on the app. These seems to pass the online tests of authenticity, but everywhere I read online says not to order on Amazon b/c most are counterfeit. I, for one, do not like bass to be emphasized at all and despise boomy bass that overwhelms all the other frequency ranges.