Sample rubber bands from each batch are subjected to a variety
of quality tests. One such test measures modulus, or how hard
a band snaps back: a tight band should snap back forcefully
when pulled, while a band made to secure fragile objects should
snap back more gently. Another test, for elongation, determines
how far a band will stretch, which depends upon the percentage
of rubber in a band: the more rubber, the further it should
stretch. A third trait commonly tested is break strength,
or whether a rubber band is strong enough to withstand normal
strain. If 90 percent of the sample bands in a batch pass
a particular test, the batch moves on to the next test; if
90 percent pass all of the tests, the batch is considered
market-ready.
