I believe it is 20,100mcd or 20,800mcd or some such horse puckey...let me check the website and see...BRB...
OK, the Arc AAA LE is 20,100mcd, and the Arc AAA PE (the 2003 edition) is 20,800mcd. I don't have measured brightness readings for the AAA standard (I got them before I got a photometer), but they should be around 20,000mcd for the white version. Just a guess, mind you, but an educated one.