Massdrop x Koss ESP/95X Electrostatic System Headphones Description: Condition: New Opened BoxFeatures:ESP/95X Electrostatic HeadphonesAcoustic principal: Circumaural open-air design with minimal acoustic dampingDiaphragm: Ultra-low-mass 1.5-micron C-grade polyester film coated with semiconductive materialDiaphragm radiating surface area: 7 sq in (45.6 sq cm)Frequency response: 8 Hz–35 kHzHeadband: Stainless steel, extendableHeadband cover: Wide leatherette-style vinyl with 12mm-thick polyethylene foam paddingYokes: Horizontal and vertical pivo