Tensun via Amazon offers its Tensun International Travel Plug Adapter with 4 USB Charging Ports in Black or Blue for $15.99. Coupon code "T8IQMKQV" drops it to $12.99. Plus, Prime members receive free shipping. That's tied with our mention from a month ago and the lowest price we could find by $10. 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. Deal ends November 30.