That first product, is what I use, and it's excellent, but the price is outrageous. I just got a e pack of these, with the cover, thru ebay, for $7.45, with free shipping. Sealed and new.
Is there any difference in oils that do not have the W, if the viscosity rating is low enough. In other words, would a 10-30, be different than a 10W-30, since they both have the same range?