15A Plug, 15A & 5A Sockets, BS546 &BS372
The front has the IRL logo, and the words 'British Made' around it. There is a letter E for Earth just below the top centre hole.
The chamfered edges are marked 5A, referring to the two pin sockets on each side.
15 Amp, BS546.
Text in the centre reads 'PATENT APPLIED FOR'.
The side sockets as BS372, 5A.
The front sockets are both 15A - BS546 for the 3 pin and BS372 for the 2 pin. Note the slightly narrower spacing of the 2 pin socket compared to the 3 pin.
The case is secured with two screws, one in each corner.
The two smaller screws either side of the earth pin secure the contact assembly into the bakelite base.
Note there is no fuse for any of the outlets.