How do the two types of leather used for the backpack's outer material and lining differ?

The outer material is Nappa lambskin, and the lining is Cow Leather^[1][2]. While the inside of a bag is often lined with fabric, the LANIÈRE 07 BACKPACK uses genuine leather for both the exterior and interior, finishing it with different types of leather inside and out^[3][4].

Generally, lambskin and cowhide show distinct differences in density and flexibility. Lambskin is thin, has a delicate grain, and drapes softly; in particular, leather that has undergone Nappa processing naturally preserves the surface grain and folds flexibly. In contrast, cowhide has dense and tough fibrous tissue, making it resistant to friction and firmly supporting the bag's shape. This construction places tough cowhide on the lining, which is prone to scratching as belongings move in and out, and arranges flexible lambskin on the exterior surface that touches the body.