Heritage Audio OST-4 V2.0 500 Series Rack with OS Tech The Heritage Audio OST-4 V2.0 500 series enclosure is designed for racking any and all 500-series modules and devices, including ‘double wide’ modules and even the most demanding Class A and vacuum tube designs. The OST-4 V2.0 enclosure features Heritage Audio’s On Slot Technology, providing maximum protection, [...]