I call it 7" circumference, but it depends on where you measure. Right behind the sulcus it's just a hair over 6", but then it tapers out to a nice 7" girth, then down at the base it gets thicker again to about 7 1/2". From above I can't see an increase in width at the base, so I guess the profile goes from oval to a more circular cross section. Doesn't much matter, that part has never penetrated anything.