The ProX X-HH711 Universal Clamping Headphone Holder for Vertical Surfaces, Poles and Stands is made from high-quality steel, to be durable and strong, and capable of holding lightweight to very heavy headphones without bending or breaking.  It has a locking knob with a nylon/rubber tipped screw and protective foam padding to protect your stands or case/workstation.  An easily adjustable design allowing fitment on to most any vertical surface of different thicknesses.  Ideal for speaker stands, microphone stands or other round items.  They are easy to remove and install.