An SM52 SE machine is a "Special Edition" machine. It was only available for a short time and gave the buyer the option to save money on the machine leaving some of the addon options off the machine. SE machine may or may not have blanket wash, roller wash, impression cylinder wash and gave the buyer the option to get autoplate or EZ Plate. If you are buying a used SE machine you need to find out what options come with the machine as some may not be included on the machine. SM52-4P means it has a perfector.