Darned if I know the brand. Whatever Harbor Freight had.
Holding up better than I expected, but at $18 apiece if I use several, so be it. I've got about 37 feet of cut to make, and I've done 7 feet so far. Still on the first blade.
I'm just using the led beam on the front of the saw to guide it. The welds along the edges will hide any irregularities. On the longitudinal cuts on the 3×3 rectangular steel tubing (cutting to non-standard U-tube size) there isn't anything to clamp a guide to. Constructing tapered semi-trangular cross sections out of rectangular tubing is the tough part.
The remnant of the horizontal top cross brace U-tube after cutting will form the top 'half' of the bottom cross brace after the remnant is trimmed with a third longitudinal cut. So three 5.5 foot cuts will give me the top cross brace and the top half of the bottom one. I'm not set up to roll form the bottom and side braces, so am doing them the hard way.