That's a very good point Fred, especially with the dusting brushes. And I saw that on this seller's XXXs that have original dusting brushes, the rubber bumpers are missing because surely the rubber had disintegrated long ago.
(And this makes you wonder about the condition about the rubber air-sealing "lip" inside the brush since that "lip" and the bumper consisted of one single piece of rubber. That "lip" is vital for good performance with the dusting brush because it keeps the suction from getting diffused and lost through the long bristles, and also keeps the bristles from curling inward and getting sucked up inside the brush housing.)
The early XXX Electrolux dusting brush and the floor brush had black rubber bumpers that have held up very well. I have several each of these tools with beautiful, intact bumpers.
When the LX-style rug nozzle was first introduced in 1949 as an optional (extra cost) accessory for the XXX, it had a gray rubber bumper that also holds up well. The same type of rubber (or, at any rate, the same color) was used for the bumpers for the floor tool and dusting brush. I've seen a lot of gray-rubber floor brushes with intact bumpers but hardly ever see a gray-rubber dusting brush with intact bumpers because for some reason the gray bumper on that tool does not last a long time.
Then when the LX came out and the XXX was sold as a lower-tier model, the rubber for all three attachments (for both models) was a bluish-gray rubber that has not held up at all well. The dusting brush bumpers become petrified and brittle; pieces of the rubber crumble off every time you handle the brush. The floor brush and rug nozzle bumpers develops a strange sort of "skin condition" where the rubber deteriorates and develops a sort of "leprosy" for lack of a better description: It develops crumbling blisters and pitting and then eventually becomes dry and brittle like the dusting brush.
Clearly Electrolux changed the rubber formulation for blue-gray rubber bumpers, or else the different dye negatively impacted the rubber somehow.
The only attachment that seems to have bumpers and rubber parts that have consistently held up is the first version of the floor polisher attachment. A variety of colors and materials for the bumper and "snout" were used for the roughly 10 yeas that version of the polisher was made: Dark gray rubber, light gray rubber, deep turquoise rubber, bluish-gray rubber, and then ultimately some type of dark blue-gray plastic for the last models made. I've never seen a polisher with "bad" bumpers, and I've seen a lot of 'em!
More than anyone probably wants to know, or cares about... heheh.......
