You don't need my zip code, but here is it anyway: 8450 Bredene (Belgium).
I checked it with USPS: http://ircalc.usps.gov/intl_speed.asp?CID=10033&MailType=envelope&Pounds=0&Ounces=13
Checked for 0 pounds, 13 ounces, in an envelope. That is about 370grammes, should be more than enough for such...