This is a headphone holder for an electronic drum kit. I designed it for my Roland TD 07 DMK drumset, and it fits the main structure, which has a diameter of 40mm. Any model with a 40mm or smaller structure will be compatible. The photos show how to assemble it. The holder can accommodate headphones with a headband wider than 5cm. In terms of printing, it needs supports, but they are very easy to remove without tools.