12mm power entry

[baadc0de]

I've got a 1U case with a predrilled 12mm hole on the back, seemingly designed for a power entry socket. I'd prefer to feed it 220Volts and have the PSU inside the case. I'm buying at farnell, can anyone help me find a good socket I could use, I'm totally lost among all the sockets and clips and ..

thanks in advance,
B.