Front, back, left or right
One piece slides onto a desk edge and carries the headphones on a cradle underneath or alongside. Front and Back hang the headphones outside or under the desk; Left and Right run along the edge with a gradual 90° twist below the clamp, so the cradle ends up parallel to the desk rather than across it.
Three measurements drive it: the table thickness between 12 and 60 mm, the holder height from the underside to the headband resting surface between 40 and 160 mm, and the headband width front to back between 15 and 70 mm. The retaining lip rises 3 mm above the headband height and never less than 8 mm, which is what keeps the headphones from sliding off the cradle.
The grip works by interference: 0.8 mm by default, measured between the table thickness and the relaxed contact gap, and the bottom silicone recess follows it. Dots default to Ø10.5 × 3.15 mm with 0.4 mm of extra diameter per recess and a 1.575 mm deep top pocket. Front and back exports rest on their broad face at Z = 0 and left and right exports stand on the cradle, so check the fit and the load capacity against your own desk and headphones.