The grip on the echo is NOT tight so it can freely rotate within the mount - great for you to cable manage! There is also a small slot between the top clip and the bottom of the shelf clamp, which you can use to wind the cables.

The shelf here is an Ikea Kallax unit, with the clamp on the thick portion.

Print instructions

The Echo doesn't get hot enough to warrant PETG. PLA works fine here! The pictured holder has an infill of 20% and works fine.