Audio-Technica ATH-M30x Professional Monitor Headphone Bundle with FiiO A1 Portable Headphone Amplifier This bundle includes the Audio Technica ATH-M30X Studio Headphones, the FiiO A1 Portable Headphone Amp (Silver), and a K&M Microfiber Cleaning cloth. Audio Technica Box Includes: Audio-Technica ATH-M30x Monitor Headphones (Black), 1/4" Screw-On Adapter, Carry Pouch, Limited 2-Year Warranty. Product Highlights Audio Technica ATH-M30X: 40mm Neodymium Drivers, Circumaural, Sound-Isolating Design, Tuned for Mid-Range Detail, Collapsible Design, Single-Sided Cable Exit, 3m Attached Cable, Includes 1/4" Screw-On Adapter, Includes Carry Pouch Product Highlights Fiio A1: Tiny Size, Hardware Bass-Boost Settings, Four EQ Modes for Maximum Flexibility, Rechargeable Lithium-Ion Polymer Battery, 3-Color Status LEDs, 20 Hz to 20 kHz Frequency Response.