Actually, PU can have leather in it, but it doesn't always. Here's a quote from:
http://en.wikipedia.org/wiki/PU_leather .
"Bicast leather (also known as
bycast leather or
PU leather, sometimes described as
split leather) is a material made with a
split leather backing covered with a layer of
polyurethane (hence the term PU leather) that is applied to the surface and then embossed. Because it is only used for the backing, the leather portion of this material is generally not visible in finished goods made from Bicast. Bicast was originally made for the
apparel industry for glossy shoes, and recently was adopted by the
furniture industry. The resulting product has an artificially consistent texture that is easier to clean and maintain, as is the case with most plastic materials."
Here's more info from here:
http://www.ebay.com/gds/PU-LEATHER-COMPARED-TO-GENUINE-LEATHER-/10000000008377991/g.html .
"PU (Poly) Synthetic Leather is a man made material that will represent the look and feel of Genuine Leather but in fact is NOT. This PU material is far less durable, considerably cheaper in cost, and may not last long if used often. This material is extremely pliable and will stretch kind of like a spandex material. It has a more shiny appearance and generally is far less thick than real leather. Grooves similar to your fingerprints are mechanically pressed into the material to give it that REAL look. These grooves are far less defined and are hairlike impressions. This material for the most part is Waterproof and easily cleaned or maintained. For persons on a tight budget this material is the way to go. It's about half the cost of real leather products and will still look awesome in your collection.
If your Strict on your Leather policy, this IS NOT the way to go."
That last part I bolded is what keeps me avoiding PU. Idk, I know it's a small chance that there is any leather, but I'm still weary.