Harman Audio offers the factory-refurbished AKG K512 MKII Headphones in Black, model no. K512MKII-Z, for $17.95 with free shipping. That's $15 under the lowest total price we could find for a new pair. They feature a frequency response of 16Hz to 20kHz, 3.5mm jack, and 6.3mm jack adapter. A 1-year AKG warranty is provided. Deal ends May 24.