RVP is a big city gas. it is for big cities who require more regulations on gas. It's not winter/summer gas, it's the diffrence in the weights,one wieghs 7.9 and the other weighs 9 lbs a gallon. it has something to do with clean air and vapor recovery. the big problem is Wall Street day traders are absolutly breaking the U.S out of pure greed and they are making all fuel jobbers and convience store owners look like they are gouging prices. OK I fell better.