Quoting Pete Turnbull <pete at dunnington.plus.com>:
I don't think you mean C5 (or C6). That's a
3-pin, the one sometimes
called "mickey mouse ears", and one of the less-common types. I mostly
see it on Toshiba laptop power supplies.
C7 (cord connector) and C8 (inlet) is 2-pin. It's the one often
referred to as "figure of eight", and the only common 2-pin.
https://en.wikipedia.org/wiki/IEC_60320