<P> NASA makes significant use of touch fasteners . Each space shuttle flew equipped with ten thousand inches of a special fastener made of Teflon loops, polyester hooks, and glass backing . Touch fasteners are widely used, from the astronauts' suits, to anchoring equipment . In the near weightless conditions in orbit, hook and loop fasteners are used to temporarily hold objects and keep them from floating away . A patch is used inside astronauts' helmets where it serves as a nose scratcher . During mealtimes astronauts use trays that attach to their thighs using springs and fasteners . </P> <P> The Slidingly Engaging Fastener was developed to address several problems with common hook and loop fasteners . Heavy - duty variants (such as "Dual Lock" or "Duotec") feature mushroom - shaped stems on each face of the fastener, providing an audible snap when the two faces mate . A strong pressure sensitive adhesive bonds each component to its substrate . </P> <P> There is a silent version of touch fasteners, sometimes called Quiet Closures . </P> <Ul> <Li> ASTM D5169 - 98 (2010) Standard Test Method for Shear Strength (Dynamic Method) of Hook and Loop Touch Fasteners </Li> <Li> ASTM D5170 - 98 (2010) Standard Test Method for Peel Strength ("T" Method) of Hook and Loop Touch Fasteners </Li> <Li> ASTM D2050 - 11 Standard Terminology Relating to Fasteners and Closures Used with Textiles </Li> </Ul>

Which is the hook and which is the loop on velcro