All stands come in two versions – regular and low. Regular stands, at the lowest point, are about four (ish, I’ve never measured) feet high. Should one desire to have the light lower than that, one must use the ‘low’ version of the stand, which is pictured here.
This is a ‘low crank’, which is used for large, heavy lights – the crank makes it easier to raise and lower them.
Low cranks are also used for large lamps that aren’t all that heavy, but are a pain in the ass to carry around – since the low crank has wheels, one can just drag the giant lamp around instead of straining one’s back and the credibility of the set lighting department.