brush for robot vaccum mine is a xiaomi might be compatible with other brands.

the center hole for mounting on the reobot is 6.2*6.2mm has a snug fith with indents to prevent accidentel removels.

i wanted 4 brushes but for the legs to be at angel that would lead to week layer lines so i made them in diffrent parts.

as for the stems of the brush i used the extrusion calibration trash for the brus you can use any kind of brush i opted for that one.