21" Jacket Zipper, YKK #5 Aluminum Metal ~ Medium Weight ~ Separating ~ 546 Sky Blue (1 Zipper/pack) 21" Jacket Zipper, YKK #5 Aluminum Metal ~ Medium Weight ~ Separating YKK Color 546 Sky Blue (1 Zipper/pack) YKK aluminum zippers are made from the highest quality metal. Thoroughly tested to ensure strength & reliability. Aluminum Teeth.