I don't know, you'd have to email them. The kit that aquatic-store sells is basically the same thing (probably cost more),
"Steel Wire Suspension (for hanging light fixtures). All fixtures from the Aquasunlight "
Yeah these look identical to the one's I saw on a complete fixture a friend purchased for his reef tank, forget the brand. They are very nice, not only for adjusting the height but it's easy to get the light out of the way when servicing the tank.
We'll probably see them at HD in a few months for $0.50 a piece ;-)