Brand New unopened pair of Sennheiser HD 550s.

Description from manufacturer listing elsewhere:

Features

• Lightweight 0.52 lb. design ensures maximum comfort for extended wear
• Cushier headband padding enhances fit and reduces pressure on the head
• High-grade metal mesh construction offers durability and a premium look
• Open-back design delivers natural airy sound with incredible clarity
• Frequency range of 6 Hz to 39.5 kHz reveals hidden audio details
• Forward-angled transducers create a wide immersive soundstage
• 150 Ohm transducers handcrafted in Ireland for unmatched sound precision
• Robust earcup covers provide timeless style and exceptional durability
• Reduced clamping force ensures a relaxed fit during long sessions
• Punchy bass brilliant treble and lifelike mids deliver balanced sound

Specs

Type

• Type: Open-back over-ear headphones
• Application: Audiophile listening, gaming, home entertainment
• Driver type: Dynamic

Audio

• Impedance: 150 Ohms
• Frequency response: 6Hz–39.5kHz
• Soundstage: Angled transducer design for spatial imaging

Construction

• Weight: 0.52 lb.
• Headband: Cushioned synthetic leather with metal mesh
• Earcups: HD 500 series compatible, replaceable
• Cables: Detachable, HD 500 series compatible

Included Accessories

• Cable: Detachable headphone cable
• Accessories: Compatible with HD 500 series parts