Does anyone know what the power source for this is? "Its rechargeable 100 Volt ACDC power source will run for five hours for normal activity." To me that read

Does anyone know what the power source for this is? "Its rechargeable 100 Volt ACDC power source will run for five hours for normal activity." To me that reads as an AC-DC converter which makes little sense for a battery. The cyberdyne website describes the power source as, "Battery Drive Charged battery( AC100V)" I'm missing the significance of the AC The cyberdyne website also states, "Continuous operating time Approximately 2 hours 40 minutes" I wonder where they got 5 hours?