This vest is made from quite a unique fabric comprised of a mohair/wool/nylon mix. The fuzzy mohair lends to a super-soft finish that is unlike any other pullover we're aware of.
Normally you'd see something akin to polartec fleece or the likes, but this is made with much more natural components. This finish is achieved by knitting the fabric regularly and then heavily brushing it to bring up the mohair's natural pile.