Rugged Smartphone Case(Samsung Galaxy S4 / MHEE4)with a Built-in Retractable Hi-Fi Headset Smartphone Case:http://bit.ly/199q5El myefox.it:http://bit.ly/1f96QJN Samsung Galaxy S4 case review,efox smart e4 case review - Smartphone Case review Brand:Remix Material:PC/urethane driver unit:isound driver size:10.1mm impendance(1kHz/1 Vrms):16Ω sensitivity(1 kHz/1 mW):103dB±3dB Rated power:3mW Max input power:20mW Frequency range:20Hz~20kHz For Galaxy S4