- Design: SMFK Retro Collection utilizes vintage-style materials and finishing processes such as garment dyeing/stirring/salting/stone washing to present the retro texture of the clothing. The SMFK Fitted Diagonal Zipper Sports Jacket is inspired by the simplified structure of a retro diagonal zipper motorcycle jacket, featuring a cotton drawstring zipper design reminiscent of SMFK workwear jackets, and an embroidered cross logo on the left chest.