The Universal Audio OX Amp Top Box is a premium reactive load box, allowing guitarists to play and record their tube amp in its ideal sweet spots - from the edge-of-breakup to fully cranked - at any volume level, and with instant album-quality mic, room, and speaker cabinet emulations at the turn of a knob. Featuring Universal Audios breakthrough Dynamic Speaker Modeling, OX emulates speaker breakup and cone cry like no other box on the market. Its the worlds finest boutique speaker attenuator and guitar amp recording solution - overbuilt for years of home and studio use.