Brand new, unopened ■ The "K171MKII" headphones are a compact version of AKG's top-of-the-line closed-back monitor headphones, the "K271MKII". The sound quality is top-notch even with a housing that is two sizes smaller than the "K271MKII". They reproduce sound faithfully to the original sound source without any monitor headphone-like coloration. ■ The soundstage is somewhat close, with a unique sharpness in the high frequencies, making them very clear. The low frequencies have a tight outline and are clear, but their presence is somewhat reserved. Because of the high sound resolution, you can clearly hear everything from the high to low frequencies. ■ These are "on-ear type" headphones with ear pads that sit on top of the ears, and they feature strong side pressure. Thanks to this, they provide sufficient sound isolation, allowing you to concentrate on monitoring without being affected by ambient noise. ■ They are equipped with AKG's unique acoustic technology, the "XXL Transducer," which is also used in the higher-end models "K271MKII" and "K240MKII". This acoustic technology, developed for professional models, incorporates "VariMotion Technology," which controls unnecessary vibrations by varying the thickness of the diaphragm, and a "TWO-LAYER diaphragm" developed with two different materials, to reproduce clear mid-high frequencies that capture even the most delicate sounds. ■ They are equipped with a "bass tube function" that reduces the low-frequency expansion typical of closed-back headphones. The low frequencies are tightened, and the sound resolution is improved. The sound clarity is very clear, and you can accurately distinguish even delicate sounds. ■ The headband employs a "self-adjusting mechanism" that adjusts to the size of your head, making it feel less heavy on your head and providing a comfortable fit without stress even during long hours of use. ■ The cable is detachable, and two types are included: a straight cable and a coiled cable. ■ Headphones ■ Type: Dynamic, closed-back ■ Sensitivity: 94dB SPL/mW ■ Frequency Response: 18～26,000Hz ■ Maximum Input Power: 200mW ■ Impedance: 55Ω ■ Input Connector: 3.5mm stereo mini-plug (gold-plated) ■ Cable: Detachable, single-sided ■ Weight (excluding cable): 200g ■ Accessories: 3.0m straight cable, 5.0m coiled cable (when fully extended), synthetic leather ear pads, velour ear pads, standard plug adapter (screw-on type, gold-plated)