The Sound Devices A20-Shelf is a 1 RU, 19" rack shelf designed specifically to accommodate two A20-Nexus receivers or one A20-Nexus and one PowerStation-8M side by side. An A20-Nexus or PowerStation-8M can be mounted to the left, center, or right of the shelf. The shelf's rack ears have multiple fixing holes, allowing the depth of the shelf to be adjusted. The shelf has no front lip to block the touchscreen on the A20-Nexus receiver.