Plastic, aftermarket/generic duster attachment with partial soft horse hair bristles*
*Bristles are a combination of stiffer nylon strands interspersed with soft horsehair.
The nylon bristles serve to shape and prevent the brush from losing it's roundness, while still maintaining a degree of softness (from the horsehair), much more so than similar brushes that are 100% made of stiff nylon or plastic bristles.
This dusting accessory tool fits most vacuum wands that use the standard 1-1/4" diameter wand fit.
That includes, Rainbow, Kirby, Electrolux, most Sharps, Eureka, Kenmore, Dirt Devil, Royal, Singer, Bissell, Regina, Oreck mini-canisters, Central Vacs, and many, many, other brands.
(Not for Miele, Bosch, or other vacuums using 35mm wands)
If unsure, measure your vacuum wand end to confirm that it has a 1-1/4" diameter hole.