Directly powered by USB no need for extra power adapter. World’s First USB Powered Manual Swipe Smallest Magnetic Card Reader/Writer MSRX6 is designed in USA to offer a card reading/writing solution for ISO 7811-6 formats. MSRX6 is the smallest USB Magnetic Credit Card Reader Writer 1/4 size of MSR206 MSR606 MSR605 and works on Mac OS.