PRECISION TUNED AUDIO - At the core of the A/550’s brilliance is its Koss engineered RLX44 54 ohm drivers and open-back design that delivers an exceptional level of sonic accuracy and transparency with a wide frequency response of 12-22,000 Hz. PREMIUM DESIGN - Meticulously crafted from premium materials like stainless steel, aluminum, ultra soft velour and vegan leather. MAGNETIC EAR CUSHIONS - A/550 features velour wrapped magnetic ear cushions for convenient storage, cleaning and simplified ear cushion maintenance. LIGHTWEIGHT DESIGN - At just 287 grams A/550 feels impossibly light, yet remarkably durable, ideal for extended listening sessions. THE PERFECT FIT - A soft, fabric headphone, auto adjusting head sling and D-Profile ear cushions provide the perfect fit, seal and sound. ENGINEERED IN MILWAUKEE - Designed from the ground up in Milwaukee, WI A/550 represents the pinnacle of acoustic engineering and design. MINI XLR - A stunning detachable braided and jacketed cord with Mini XLR connectors and 3.5mm to 6.3mm adapter allows for expanded connectivity and portability. BALANCED INPUT - Mini XLR supports balanced audio connections with compatible third-party cables LIMITED LIFETIME WARRANTY - A/550 stands as a statement of confidence in quality, durability, and long term listening and is backed by Koss's Limited Lifetime Warranty. The Koss A/550 Open-Back Headphone represents the pinnacle of acoustic engineering and design. Meticulously crafted from premium materials including stainless steel, aluminum, ultra-soft velour and leatherette, every detail has been considered to deliver unparalleled performance, durability and comfort. Koss engineered RLX44 54 ohm dynamic drivers specially designed for A/550 incorporates a multilayer polycarbonate diaphragm, precision-machined Neodymium magnet, and lightweight Copper-Clad Aluminum voice coil housed within a 44 mm reinforced resin frame This advanced configuration delivers breathtaking high-fidelity audio with a frequency response of 12 Hz to 22,000 Hz. A/550 reveals exceptional detail and nuance with deep bass, crystal-clear highs and a rich, balanced midrange for an extraordinary listening experience.