This the plastic shutter / slider / regulator that fits on the hose handle for some Nilfisk vacuum cleaners.
Suits:
Nilfisk GD1000
Nilfisk GS80
Nilfisk Business GD1010
Nilfisk Business GDS1010
Nilfisk Business GDS2000
Nilfisk Business HDS2000
Nilfisk Family GD1005
Nilfisk Family GD2000
Nilfisk Family GD910
Nilfisk Family HDS1005
Nilfisk Family HDS1005