BV
That is NOT a Electrolux or Eureka floor brush. It is a generic fit-all floor brush commonly sold in vac shops, even to this day! It just comes with different necks for different applications....1.25" for most normal vacs such as Eureka & Electrolux, & then the Hoover-style neck as you have with the metal pin. There may also be a Filter Queen version out there too.
Rob