A socket outlet containing a 10mA RCD which can accept virtually any plug.
This item was obtained on eBay from a Chinese registered seller shipping items from the UK.
Externally the casing is solid, labelled correctly and has two points for fixing screws. This would fit into a metal backbox as used in the UK, but only if it was the extra deth 47mm type.
When power is applied, the Test and Reset buttons work as expected. Testing with an RCD tester reveals that the device does operate correctly and within the claimed specifications.
Internally the circuit board is of reasonable standard, and the wiring is copper as would be expected. Contacts are either brass/copper or some similar alloy.
All of the RCD functionality is provided by a single 8 pin chip. A small sense coil is used with the line and neutral conductors passing through the centre of the coil - this is a common arrangement for electronic RCDs.
Although made to a reasonable standard, this item is not suitable for use in the UK as the socket outlet does not comply with BS1363 (although BS1363 plugs will fit into it). It is only rated to 10A which prevents it from being used on most circuits found in UK homes - typically they are 32A rated, less commonly 20A or 16A.
10A circuits can be installed in the UK, but would be extremely uncommon for socket outlets.