Jeff is right with item but they offer in a 30x30mm Profile only a 6mm opening Profile, the 80/20 i think has a 8mm one. And in the normal version it's quite heavy. And there are not so much assecceries like the Profile 8 versions. I ordered some stuff from alcom international. Very good company too and offers a 30x30 profile with a 8 mm Profile nut
http://www.alcom-international.de/produkte.html