This clamps to the 1 7/8″ OD pipe and a diagonal 2×4 wood brace can be connected under the nut and washer before clamping.
Adjustable in height.
(4 Per Pack)
To avoid confusion when buying pipe that fits in this, the industry standard calls the pipe size as 1.5″ schedule 40 but the O.D. is actually 1 7/8″.