The new headphone holder including an innovative table clamp is a
  guaranteed secure and comfortable holder for your headphones. The
  holder protected with soft rubber can easily hold 2 standard
  headphone sets and 2 in-ear headphones can additionally be hung
  on the front. The headphone holder can be fixed in four different
  directions using the clamping screw. In addition the holder can
  be rotated from any position by 90°. The clamp can be extended
  from 0 to 48 mm allowing it to be mounted on a wide variety of
  tables. The stable metal construction with high quality plastic
  inserts guarantees a secure and strong attachment. The cleverly
  shaped clamping parts allow the clamp to be used on smooth
  surfaces and round-shaped tubes.