The zipper company YKK produces everything in-house, including its zipper-manufacturing machines and shipping boxes.
Apparel Resources, Tiny Fox Lab

The YKK zipper company does everything in-house to ensure consistent quality and speed of production. It manufactures its own zipper-manufacturing machines, makes the shipping boxes, smelts the brass, spins and twists the thread, and weaves and color-dyes cloth for its zipper tapes. – Tiny Fox Lab Facts

Preview photo credit: Apparel Resources
Source: slate.com/business…