Kangaroo

Kangaroo is the outlier of the leather world. Weight for weight it is markedly stronger than cattle hide, because its fibre structure is more uniform and runs parallel to the surface. That means it can be split far thinner than calf while keeping its tensile strength — so an upper made from it is lighter and more supple without giving up durability. Ours comes from Gruppo Paccapelo, a Montegranaro family that has specialised in rare skins for over a century, in a soft-but-firm article made for footwear.

For a sneaker the appeal is immediate: a thin, light, glove-soft upper that still resists tearing, abrasion and stretching, and moulds to the foot rather than breaking down. It is the material generations of footballers have insisted on for exactly these reasons. On the SF-01 it gives a pair that feels barely there on the foot but is built to be worn hard.