This is an open box Musical Fidelity V90-HPA Headphone Amplifier. Comes in original box with all components. Manufactured in 2014 in Taiwan, and designed in the UK.

This did power on just fine, with the blue power light visible in the second photo. Beyond that I did not test other functions, as I don't have additional equipment, and frankly do not have the expertise in this kind of thing.

That being said, I did include photos of the user guide, so you can tell for certain what I/O there is.

Don't hesitate to ask questions as needed! And if you need additional photos let me know.