$2,499 Sennheiser HD 820 Flagship Headphones, open box, everything included

$2,499 Sennheiser HD 820 Headphones
Top of the line, Flagship model latest edition. Check this ad on usaudiomart site for tax-free pricing.
New condition, I bought them to try the closed back design.  Listened for 5 hours and decided to stay with my open back Hifiman HE1000SE.
My loss is your gain.
Everything is included: original packaging and display box, two cables 1/4" and 4.4 Balanced.
Search the net for multiple reviews in audiophile magazines

The Sennheiser HD 820 are closed-back stereo over-ear headphones offering detailed and accurate audio reproduction for audiophiles, mixing and mastering engineers, and music aficionados in studios, listening rooms, and on the go. Their closed-back design delivers up to 26 dB of passive noise cancellation and incorporates concave glass covers, which reduce resonance by reflecting sound to a dedicated absorber. Sennheiser's dynamic Ring Radiator transducers provide a maximum SPL of 103 dB and a wide frequency response of 12 Hz to 43.8 kHz.

Handcrafted microfiber ear cushions and a sturdy metal headband with an internal damper offer comfort and stability during wearing. A 10' impedance-matching cable allows distance between you and your headphone amplifier, while balanced 4.4mm and unbalanced 1/4" plugs enable versatile connectivity.

The HD 820 headphones ship with a microfiber cloth and a storage box for simplified transport.

Visual and Audio Transparency Dynamic Ring Radiator transducers are fitted with concave glass covers, which reveal the look of the technical components within and reflect sound waves from the rear of the transducer to an absorber, yielding minimal resonance Carefully Selected Components From the handcrafted microfiber ear cushions that insulate the listener from ambient noise to the silver-cladded OFC cables, gold-plated plugs, and robust metal headband with an inner damping element, the components work together to deliver comfort and uncompromising sound Audiophile Connectivity A specially tuned symmetrical, impedance-matching cable with low capacitance can be terminated with a balanced 4.4mm gold connector or an unbalanced 1/4" gold plug