No-sew trouser hook and bar

I'm trying to find the clamp-on (not sewn on) trouser hook
and bar sets like:

I used to have several sets, but they are all gone. I'm
making DGD's first genuine wool tartan (at $$$/yard)
Nationals skirt for Highland Dance, and they are always made
adjustable to accommodate the growing girl's waistline. I
don't like the look of the sewn on ones, anyone know where
the clamp-on sets are available in the U. S.?