Here is a simply explanation of Amps, Watts and Volts. Electricity is measured in terms of Amperage, Voltage and Wattage. Amperage (amps) is a measure of the AMOUNT of electricity being used. Voltage (volts) measures the pressure, or FORCE, of electricity. The amps multiplied by the volts gives you the Wattage (watts), the measure of WORK that electricity does per second.
Think of electricity in these terms. Electricity flows through a wire is like water flows through a garden hose. The amount of water that can fit through the hose depends on the diameter of the hose (amps). The pressure of the water depends on how far open the faucet is (volts). The amount of work that can be done (watts) depends on both the amount and the pressure of the water (volts x amps = watts).
Many home EV Chargers are 15 to 30 Amps so that's many people who want a faster charge look for a 40 Amp Charger, like the JuiceBox Pro 40 (amps).
You can read more about the JuiceBox Pro 40 Electric Car Charger.