This is an accessory holder/mount that clips onto the wand of the Dyson v7/v8 motorhead wand.
This is a customizable holder. You can specify the # of accessories. I would not specify more than 3 accessories, as the accessory holders will start to overlap each other. So any value from 1 to 3 should be fine. I would recommend that you tweak the shaft_r and accessory_r variables if needed. Every printer will be a little different and a slight difference can make the holder too tight or too loose.
If the holder is too loose on the wand, use a slightly smaller shaft_r value. If its too hard to put the accessories on, then use a slightly larger accessory_r value. Possibly adjust the ear_d value too if the ears are tight.