My friend, Tom, passed away about 4 years ago,, so i cannot ask him about the dyes that are injected into the oil when it goes into packaging.. I'm sure,,, like PALE OIL ( a seafoam thread a week or so ago) there are 15 different "part numbers" and 15 different versions.. If you bought a gallon of YAMALUBE and it was the SAME COLOR as the gallon of WALMART oil or citgo oil,,, you'd probably be pissed off that you'd just spent DOUBLE the price for the SAME STUFF!!!! There are a half dozen different "qualifying" markets out there from jaso to api to sae to etc,etc,etc,, and I CANNOT and DO NOT keep up with them all.. the ' W " that I was speaking of in the equation 10-W-30 motor oil was for an example.. If the JASO spec or the TC spec says that "W" is for WATERCRAFT ,,, for THEIR APPLICATION,, they are correct... The SOCIETY OF AUTOMOTIVE ENGINEERS and also the AMERICAN PETROLEUM INSTITUTE refers to the "W" as for use in WINTER applications.. I'm SORRY if I confused you guys or gave you some OLD information.. I got out of school TWENTY FIVE YEARS AGO and always got that question RIGHT on the "what does the "W" stand for in 10-W-30... Remember.. API services were SE when I got out of school!!!