It's the three letters that are most likely on your zipper right now. It's the Japanese zipper brand that is so well and cheaply made that it cannot be knocked off because knock off brands will be more expensive and more inferior. If you ain't got YKK on your zipper you ain't shit.
"Ima show you how to wild out like Jack Trippa
Let me bambino on you snippas
YKK on yo zippa
Lick you like a lizard" -Outkast "so fresh so clean"