These are a stunningly preserved, fully working pair of vintage P.W.B. Dyna-X headphones from Peter Belt Electronics. These feature rare, vintage orthodynamic / isodynamic (planar magnetic) drivers that produce highly detailed, low-distortion audio. The ear pads, plastic grilles, and headband are in incredible, near-mint cosmetic shape with no cracking or deterioration. Fully tested with balanced audio channels and a clean sound signal.