Amazing piece in amazing condition - for anyone  in the market for an OX Amp Top Box, this is a great deal.  

OX is a premium reactive load box and guitar recording system, giving you perfectly studio-miked amp sounds from your favorite tube amp. OX lets you play and record your amp in its sweet spots — from huge clean tones and edge-of-breakup to fully cranked — at any volume level, and with mic, room, and speaker cabinet emulations at the turn of a knob.

Featuring Universal Audio’s breakthrough Dynamic Speaker Modeling, OX is the first system to accurately emulate speaker drive, breakup, and cone cry — making it the world’s finest speaker attenuator and guitar amp recording solution.

This one is in excellent condition with the original box.  It's quite the score!

A More Flexible Way to Use Your Tube Amplifier

With the Universal Audio OX Amp Top Box, you can play your favorite tube amplifier at its sonic sweet spot at any volume level. And that's just the start — featuring UA's Dynamic Speaker modeling technology, you'll be able to access dozens of spot-on mic and guitar cabinet emulations. Premium analog components and one of the world's best reactive load circuits ensure you'll hear all the dynamics and harmonic complexity your amplifier has to offer. The OX Amp Top Box is a powerful solution for recording, allowing you to achieve those cranked-amp tube tones at any volume level. Many recording guitarists prefer this recording method for maximum sonic control. Instead of a speaker cabinet, plug your tube amp into the Universal Audio OX Amp Top Box to explore a whole new range of tonal possibilities.