Tensun via Amazon offers its Tensun International Travel Plug Adapter with 4 USB Charging Ports in Blue for $15.99. Coupon code "AV7UPEX9" drops it to $11.99. With free shipping, that's tied with our mention from a month ago, $27 off, and the lowest price we could find. 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.