^start of string
\d{4}a digit, repeated exactly 4 times
-the literal - (4510 / 558 / 2D16)
{4}matches exactly 4 characters from the set below:
a-zone character from a (9710) to z (12210) (case insensitive)
-the literal - (4510 / 558 / 2D16)
\d{5}a digit, repeated exactly 5 times
$end of string, or before its final line terminator
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters