Operation confirmed. While I believe it's in good condition, it is still a used item, so please check the images and understand before purchasing. The SONY MDR-CD900ST is a studio monitor headphone developed jointly by Sony, boasting world-leading technology, and Sony Music Entertainment, with its refined and well-honed sense and know-how in sound creation, making it a completely professional specification. [Specifications] Sealed type, 63Ω, 106dB, 5-30,000Hz