Nikon SP Exposure Meter Booster

This was displayed in a glass case as part of a collection.
I am selling it due to space constraints.
When you turn the dial, the hands move, but I cannot confirm if it is operating correctly or at all.
What is shown in the photos is everything included.
The leather case is included, but it shows signs of age-related deterioration.
Ideal for repair or as a collectible.

Nikon
Film
SP
S
S2
S3
F