Source with many more images: Century 21 Props - Rack cabinets (Space: 1999 Catacombs)

The main unit featured was in the corner of the SHADO headquarters in UFO. Even within UFO episodes, details change as the prop is refurbished. For Space: 1999, some sections are have been swapped around, altered and in one case replaced. The top panel in UFO, with 3 round dials, swaps with the one at knee height, with a square red dial and four green wheels. Two of the middle panels are altered, and the central one has been replaced entirely.