Silent Velcro is a non-existent theoretical product that is identical to Velcro but does not produce any sound when the two halves are torn apart. The movie Garden State makes reference to such a product, invented by the fictional character Jess Belliveau in 2004 whilst searching for the fountain of youth.
External link
Halfbakery discussion page including the comment "Velcro USA developed it for the army. Unfortunately, it's classified".