Genuine Kirby vacuum cleaner part 152604.
The bottom plate attaches to the bottom of the power nozzle near the brush roller.
This bottom plate fits Kirby vacuums with the power drive feature, including the Kirby:
Sentria 2 and Sentria
G10D, G10, G7D, G7
G 2001 Limited Edition (G2001)
G 2000 Limited Edition (G2000)
G six, G6, G5 and G4