A cheap universal travel adapter shows that different plug groups are connected to one another at the same voltage. When the plug pins are fully retracted into the housing, they are not live; however, user error is possible because this mechanism is not mandatory. The adapter also has two USB ports claiming to provide 5 V and 2.1 A output. The review concludes that it would be safer to remove the US- and UK-style plugs and cover the openings, using the product only as a USB charger and universal socket.
Why it matters
The main importance of the review is that it shows safety in travel adapters cannot be assessed solely by plug compatibility. When retracting the plugs into the housing does not depend on a mandatory mechanism to cut off the electricity, user behavior can directly become an electrical risk. This concerns people using a practical solution that combines sockets and USB charging in a single housing across different countries; how unused plugs are physically disabled becomes critical. However, the review leaves open the question of under which usage conditions and to what extent this design can be considered safe, as well as how well the USB outputs can meet their stated performance.