This turbo charger has 24W output (12V*2A). The internal circuit of the battery pack will step the voltage down to 6V,
the charging current will rise to 4A (6V*4A), what why it is called 4A charger

Nitecore 4A Turbo ChargerAlways have full power in your Nitecore NBP52 & NBP68 Battery. This AC charger for the NBP52 battery pack will rapidly charge your battery. In order to charge the battery pack, you plug the adapter directly into the 4.5mm charge port on the front side of the NBP52 & NBP68.

Features & Specifications

• Provides 2 amps for fast charging
• Plugs directly in the NBP52 & NBP68 rapid charge port