Bingo.Turns out these are ProSolar RoofTrac.
Not very user friendly.
I wish I had used plain ole galvanized strut.
Aluminum rails will last way longer than the typical electrogalvanized strut that the big box stores sell. That is intended for indoor use only. Hot dip galvanized strut works well outdoors but it's much more expensive where I live.Again, a piece of galvanized strut and a portable band saw is all you need to get going. Fancy extruded aluminum rails can cost more money and not work any better.
Odd that it's $41 here I suppose prices could be different depending on the store I have used them before good for mounting conduit on walls. I can see that being a good idea for ground mounting I doubt it would pass code for roof mounting. I have local solar supplier Santan solar I don't have to ship rails actually cheaper at $3 a foot then the superstrut. When you add shipping makes a difference having Home Depot locally makes sense to use those.Superstut 10 foot rail, the deep rail, galvanized, about $35.57 at Home Depot near me in So Cal. I just bought one.
10 ft. 12-Gauge Half Slotted Metal Framing Strut Channel in Silver Galvanized
Half Slot "A" Channel with SilverGalv finish
1-5/8 in. Channel Depth
Clean, paintable surface
Then there are specific nuts to screw the bolts into, end caps for appearance and can easily be cut to length with a portable band saw.