SO I bought this used TriStar MG1, works very well, very convenient small tank on wheels, which has a well made but very basic powerhead which works just fine on my apartment supplied omnipotent low-pile tan carpeting. Which got me to wondering, there were in the past much more elaborate power heads with lights, height adjustment levers, bumpers, vent control and so on which seem to be no more - at least on my TriStar. Is this because nobody really needs all of this on today's short nap carpeting? Was this needed in the age of SHAG? Shag=a=delic! Hmmmm.