Adorama offers the Astell&Kern Beyerdynamic AK T1p Special Edition Semi-Open Over-Ear Headphones for $549.99 with free shipping. That's tied with our mention from last month and the lowest price we could find by $209, although most retailers charge around $1,199. They feature Tesla drivers, 5Hz to 50kHz frequency response, and 32-ohms impedance. It includes 2.5mm and 3.5mm cables and a 3.5mm to 6.3mm adapter.