Thank you for viewing. The sound quality is fine, with no crackling or other issues. In fact, the aging process has softened the sound, making it easier to listen to. * The head pad has been replaced with a third-party one. * The ear pads have hydrolyzed, so we recommend replacing them. * The housing also has some stickiness due to hydrolysis. Please examine the photos carefully as this is a used item, and we ask for no returns or claims. Please refrain from purchasing if you are overly concerned about the condition. ＜Features＞ ■ The "K550" is AKG's top-of-the-line closed-back headphones, incorporating AKG's accumulated technologies, such as a newly developed 50mm driver unit and an innovative ventilation system. ■ Equipped with a large 50mm driver unit, it reproduces sound with a wide dynamic range and ample headroom. You can enjoy a wide soundstage and immersive sound, just like open-back headphones. ■ The low frequencies have a calm and mellow impression, and the clarity from the high to mid-range frequencies is excellent. The high resolution accurately reproduces the lingering sounds of cymbals and the subtle spread of reverb. ■ The headband uses AKG's proprietary "2D-axis structure." The housing rotates 90 degrees horizontally and can be folded flat. ■ The 3.0m single-sided cable uses high-purity OFC (oxygen-free copper) cable to transmit clear audio signals without distortion. ■ The plug is a straight-type stereo gold-plated mini-plug, and a 6.3mm standard plug adapter is also included. ＜Specifications＞ ■ Headphones ■ Type: Dynamic closed-back ■ Frequency Response: 12～28,000Hz ■ Sensitivity: 114dB SPL/V ■ Impedance: 32Ω ■ Maximum Input: 200mW ■ Color: Metal/Matte Black ■ Cable Length: Approximately 3.0m, OFC (oxygen-free copper) cable ■ Plug: 3.5mm stereo mini (adapter included) - Brand: AKG - Type: Over-ear - Connection Type: Wired - Condition: Slight wear on ear pads