QUALITY There are two kinds of vinyl, cast and calendared. The calendared is made by squeezing a blob of hot vinyl through some rollers into a thin (3.5-4mil) sheet. It's cheap to do, but the vinyl wants to shrink back a bit after a couple years because it was forced into a sheet without being all the way melted. When the cast vinyl is made it is completely liquid and pours in a very thin (2mil) sheet from a pool of molten vinyl. As it cools (casts) in its sheet shape, it has no stress and will maintain its dimensional integrity for much longer. This material costs about 3 times the money to manufacture, and being thinner it is a little harder to apply, but it is the only way to go if you want it to last. (And to survive the car wash). All our kits are premium 2mil cast vinyl with an expected outdoor life of 7 yrs.  If you are considering a kit with printed color like the 35th anniversary kit, they are all made with a Gerber Maxx 2 thermal resin printer.  Inkjets and paintjets (even laminated) will not give the durability necessary for automotive graphics.  The Maxx 2 melts color foil onto the vinyl as it passes through the machine.  This foil will last about 5yrs before it begins to fade.  Furthermore the 35th anniversary stripes are usually printed in black or white which have inherent longevity. You will find no better quality on the web.  You will, by contrast, find plenty of people who will sell 3.5 mil gloss intermediate and not bother to mention it.  It is very shiny, stretchy, and difficult even for me to tell from the real, so be wary.To be fair, intermediate vinyl is good for 3-5 yrs, which is fine for many applications, just make sure you get what you pay for.