Use 60Hz American Wahl 120V Corded Clippers in 50Hz Countries.

All corded clippers on American market, such as the popular Wahl brand, are frequency-specific; they run on 60Hz, 120V AC. Voltage transformers change the voltage but do not change the frequency. When you plug in clippers made to run on 60HZ (US, Canada) to a 50Hz (Europe, other countries), they will run making a terrible loud noise.
A quick and easy way to provide 60Hz 120V AC for typical American clippers is by using a car voltage converter made for the US market (from US ebay or Amazon) and a DC power supply to run that converter.
DC power supply ➤ Car voltage converter to 120V 60Hz ➤ US Clippers 120V 60Hz 👍
(CORRECTION: at 1:57 I'm saying "15.3 Amps" when it is obviously 15.3 VOLTS)