I want to replace the bridge on my Epiphone Casino and am having a real hard time feeling confident about spec'ing out replacements. Making things more complicated, I want a TOM bridge with vinyl or tusq saddles (not open for discussion really, I've decided on that course). I've got a cheapo plastic Home Depot caliper that tells me it is approximately 74mm (or possibly 73.8-9mm) from center of post to center of post. It appears to have standard posts (not threaded and no slot for adjustment. Adjustment ring is fixed to the post, threads go into the bushings attached to the body. The underside of the bridge has "B-1" stamped on it. The reason I'm asking all this is that the Epiphone TOM bridges that I've seen in the past I believe had "B-2" stamped on them. I don't know what this means. Can anyone help?