I am trying to understand what you want to plug it into, given that you mention the flattened hexagon which suggests a Europlug. You also mention the car... is it to connect to an inverter?
Europlug is a common enough thing but it exists only in certain forms. The idea is that it is a cheap, simple and compact plug that fits most European socket variants with 19mm pin centres. In theory there is no corresponding socket type because it is simply a compatibility workaround for all the other existing types, however Europlug 'sockets' are starting to appear on things like extension leads.
Any adaptor with specifically Europlug pins and a 3-pin socket is going to be a bit naughty, possibly a lot naughty, not least because Europlug - specifically the slim hexagon with inclined 4mm insulated pins - is only rated at 2.5A. So why do you want Europlug on the male side, and not one or more of the full-spec earthed 16A EU plug types such as CEE 7/4 (Schuko) or 7/6 (French)?