Ooh! Ooh! It’s … Pretty!
Omigosh, I liked the look of these in the drawings, but they are irresistible in person! They are aluminum, but the coating is almost like chrome. My Dad (Happy 85th Birthday, Dad!) says that you can definitely electrocoat chrome on aluminum, but it also polishes up beautifully by itself, and he should know after a career with Kaiser Aluminum.
The top one is separated, the bottom one is how it will look in the assembly. That red thing in the middle is a soft-ish poly plastic thingie that is meant to give a little so that somewhat out of line shafts will still turn together accurately when joined by this coupling. And you can see in the lower one, near its bottom edge, the head of the cap screw that tightens the jaw of this jaw coupling around the 1/2-inch shaft that will fit into its bore.
I bought 18-inches of shaft and a cutoff wheel. This weekend, measure twice, cut once.