Sorry, revising the question from my previous posting. What I'm really wondering is how Ishiwata EX 4130 relates to EX-O, EX-M, etc. T-Mar posted some useful stuff about Ishiwata some time ago but didn't mention EX 4130. The label says EX, then in smaller type below "4130 chrome moly triple-butted frame tubing." The fork (original, I'm pretty sure) is Mangaloy 2001.