The step down from the one for $6,000 to the smaller unit is considerable. More, in fact, than I originally thought. I went back to find the answer to your question and was told the smaller unit will run two spigots for the shower and will connect to the fancy digital control panel you see in the video. That’s about it. The complex network of pipes and wires you see costing $6,000 runs up to five shower heads, provides a steam exhaust (that’s the silver box near the bottom of the setup) plays music from your iPhone playlist and provides that cromotherapy I mentioned (a therapy based on colour, I am told).