YKK, the Japanese zipper behemoth, makes roughly half of all the zippers on earth. Founded by Tadao Yoshida in Tokyo in 1934, YKK stands for Yoshida Kogyo Kabushikikaisha (which roughly translates as Yoshida Company Limited). YKK even makes the boxes it ships its zippers in. Multiple apparel designers I talked to recalled incidents in which batches of non-YKK zippers failed to meet their standards. Likewise, you almost certainly wouldn’t nix a garment purchase because the zipper isn’t YKK.