Audio-Technica ATH-M40x Professional Headphones with FiiO A1 Portable Headphone Amplifier + HardBody PRO Full Sized Headphone Case Bundle Cutting-edge engineering and robust construction 40 mm drivers with rare earth magnets and copper-clad aluminum wire voice coils Tuned flat for incredibly accurate sound monitoring across the entire frequency range Circumaural design contours around the ears for excellent sound isolation in loud environments BUNDLE INCLUDES: Audio-Technica ATH-M40x Professional Headphones, Slappa SL-HP-07 HardBody PRO Full Sized Headphone Case, Indigo PHPA1 Portable Headphone Amplifier w/ Bass Boost EQ