PUL means Polyurethane laminate, in easy terms, a thin coat of plastic is added to the fabric (usually poliester) to create a waterproof breathable material.
The revolution of PUL has made all this new industry possible. Some women still love to use their flats and prefolds, but I don't recall a single one that has any regards to the rubber pants. Although there are other good options for waterproofing (like wool, fleece and home made diapers with old shower curtains covered by cotton), PUL is by far the most popular.
But what I have come to discover is that not all PULs are the same. Some people may argue that one is PUL and another TPU, both of those are the same, the only difference being the procedure that adheres the plastic to the poliester, the first one being a chemical one and the second a thermal.
My question is, with all the different brands I have in my stash (wow, like 4), come different types of PUL. I have a bunch of basic white medium covers with velcro. Beautifully made, Real Nappies is the most prominent brand in NZ. It's cheap and plain white (although they do have some pricier designs in their website). Well, the fabric doesn't seem to have any plastic at all. According to their website, it's called "triple layer PUL" or something to that effect. It looks the same on both sides.
Then I have 6 Fuzzibunz pockets. If you look at the inside of them, the plastic layer is right in your face. That wouldn't be a problem if it weren't for the fact that they are tiny and the plastic is sticky, making the stuffing harder than any other pocket. Yep, still doable and still gorgeous and still my first choice during the day, just wish it was less time consuming to stuff.
The Swaddlebees Econappi (I assume all Swaddlebees and Blueberry diapers use this PUL) is similar to the FB, but not as sticky. Plus the crotch are is bigger as well as the whole diaper, which is one of the many reasons they are my night diaper to go. But since I got 4 more in the Christmas sale without inserts, I just trifold a prefold and stuff it in, no muzz no fuzz. Real fast.
The Grovia AIOs are TPU. People claim the polyester side feels softer, honestly I haven't noticed the difference much. I can't say about the reverse side, since they are all sewn and it is not accessible.
An last but not least, I have a big wet bag made by a WHAM with a silvery look in the plastic side of the PUL.
So, how can one know what type it is when buying a new brand if all the tag says is "PUL"?