CONECA (pronounced: CO'NECA) is a national numismatic organization devoted to the education of error and variety coin collectors. CONECA focuses on many error and variety specialties, including doubled dies, Repunched mintmarks, multiple errors, clips, double strikes, off-metals and off-centers -- just to name a few.  

In addition to its website, CONECA publishes an educational  journal, TheErrorscope, which is printed and mailed to members bimonthly. CONECA offers a lending library, examination, listing and attribution services; it holds annual meetings at major conventions (referred to as Errorama) around the country.