You should distinguish between Genuine Leather (Top Grain or Full Grain), which offers premium durability and a natural patina, and PU/Synthetic Leather, which is more cost-effective and animal-friendly. For B2B sourcing, ensure the inner shell is made of Shockproof TPU or PC (Polycarbonate) with precise cutouts. If the cases are intended for customization (e.g., embossing or UV printing), verify that the leather surface has a consistent texture and no oily residue to ensure optimal ink adhesion or heat transfer.