Tensun via Amazon offers Prime members its Tensun International Travel Plug Adapter with 4 USB Charging Ports in Black for $12.99 with free shipping. That's $26 off and the lowest price we could find, although we saw it for a buck less last month. It features four built-in plug standards (US/EU/AU/UK), four USB charging ports (two with smart charging), and a slide-out plug release button.