Last Updated：2022/12/24
The men at the U.S. Open use what is known as an “extra-duty” ball, which means the felt on the outside of the ball is woven slightly more loosely than the “regular-duty” ball the women use. […] Extra-duty balls are the balls of choice for outdoor hardcourts, like those at the U.S. Open, except when they are not.
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The
men
at
the
U.S.
Open
use
what
is
known
as
an
“extra-duty”
ball,
which
means
the
felt
on
the
outside
of
the
ball
is
woven
slightly
more
loosely
than
the
“regular-duty”
ball
the
women
use.
[…]
Extra-duty
balls
are
the
balls
of
choice
for
outdoor
hardcourts,
like
those
at
the
U.S.
Open,
except
when
they
are
not.
