Did you get it right?
One modern grooming tool appears among the old barber equipment.

The Answer
The correct answer is: the rechargeable electric trimmer.
Here is why
- The razor, scissors, brush, combs, tonic bottles and striped pole fit the period.
- The rechargeable electric trimmer is the modern mismatch.
Why people miss it
Its purpose fits barbering, but its battery design does not fit the old shop.
What answer did you get before checking?