The drapery tool,
WAS used on the early models like the X11, and the pre-war XXX! To see the info on this go to Vintage archives January 3, 2013, thread #19227 Lux Model 30/XXX tools, starting with reply #17.
This is an extensive thread of tools for models V, X1, X11, XXX, XX, LX, and so on dealing wth machines, tools and other Electrolux goodies. This tool was called the 'teardrop.'
Alex Taber.