This is a new old stock (NOS) Lucas 2-position or single pole, double throw toggle switch (on-off), Lucas no. 34889. It is correct for many, many British cars of the sixties and seventies, including early MGB, Triumph TR4, Spitfire, Mini, Austin, Morris, big Healey, Land Rover, and many others. It is Lucas quality from the pre-green/white box era, nicer than a new production switch with better chrome plating and a smoother action.
It comes with a round trim washer (as shown). If you prefer a hex washer, let us know and we may be able to find one.
Other part numbers are 108SA and PRC5610.