When it comes to appearance, ungrounded plugs and outlets contain two prongs or holes while grounded plugs and outlets contain three. The third plug or hole in these three-prong plugs and outlets is known as a grounding wire and allows an additional path for electrical currents. Grounded outlets can safely provide power to larger devices including computers and televisions. Grounded outlets are less likely to cause short circuits compared to ungrounded outlets.
The small detachable thing is a stand-alone EU to World Adapter for your AC-powered devices when in Europe. When you don’t need to charge any AC-powered devices in EU, you can use Passport Pro as a whole to charge 4 devices. It’s the only way that Passport Pro can pass the IEC-60884-2-5 safety certification.