My base unit contains the central processor, memory, short/long range wireless communications and power unit to keep my system running. It is very slim and lightweight. Although I have friends who prefer the completely "soft" vest version, I use the belt-mounted version because it fits more with my sartorial preferences. I don’t even think about "wearing" my computer anymore, it’s gotten to be as natural as wearing a watch, (which, by the way, I no longer do). I imagine that the next step will be having my computer become a part of my body.