That's a cool attachment piece that reduces and clamps a boom rod to a stand leg (you'll have to be able to pry the top plastic cap off the leg so some of the arm can slide down into it for height adjustment, but shouldn't be too hard).
I've actually started adding a couple of my own cymbal stands to my DM10X. First was the ride, I was having so much difficulty getting it placed where I liked it and the boom had to be angled down too far for my liking.. putting it on a solid stand of its own removes any chance of xtalk AND it looks cool
Same with adding an extra crash/china type.. the more extra stands one adds the more it looks like a tricked out kit and a bit closer to an acoustic layout.
And it hasn't added any major increase to the floorspace