My RF-B45 didn't come with an adaptor, so I really wouldn't know, My RF-B45 just came with the soft case and the plug in, wire SW antenna. If there was an adaptor with it, it got lost at the store (I bought my radio at a closeout -- didn't even have the battery compartment cover. I've been using duct tape and a shim of plastic on it since 1997).
If the voltage is correct, and the polarity of the plug that goes into the radio is correct, I wouldn't worry about other particulars.