Top Grain (Cow Top)
This is a top cut of the Leather, but has been sandpapered to remove blemishes of worm, weevil and scores by barbed wired etc... After being sandpapered it is then put through an ironing process and given a chosen grain i.e. Buffalo, Alligator, Cow etc… 

Top Grain (Cow Top) Grade 2
The process if the same as above but specifying a particular grade of leather means you will be paying for a better, higher quality cut.

Split Leather
This is usually the second or third cut of the Leather, and tends to be thick and heavy, with the same process as grain corrected, and is the cheapest of the leathers.Split leather then has an artifical layer applied to the surface of the split and it embossed with a leather grain.

PU Coated Leather
This is split leather, but it is infused with a PU material to give it a smooth and softer touch. 

PVC
Polyvinyl chloride is a thermoplastic polymer, it can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is used in upholstery

Hard PVC
Is the same as above but just a thicker substance.

PU
Polyurethane material.