This fits your.
IP66 waterproof grade allows it does good job on boat.
2 USB Fast Charging
Adopted high tech of 2.1A USB fast charging port, it is almost suitable for charging all cell phones and tablets at high speed.
It can identify the electricity of your devices intelligently and charge your devices steadily and safely. Protects your devices from over-heat, over-current, over-voltage, overload, under-voltage and short-circuit.
Power Input: DC 12V-24V
USB Output Voltage: 5V
Output Current: 4.2A ( 2.1A&2.1A)
MAX Power: 21W
Product Dimension: 5.4cm x 3.7cm / 2.12in x 1.46in
Portiforium Dimension: 2.9cm / 1.14in
1 x Car Charger
4 x Blue Connector Cap
USB Charger Socket Waterproof Dual USB Power Outlet 4.2A with Voltage LED Digital Display for Car Boat Marine Motorcycle B07DDHJHLZ