$re = '/^[AC-FHKNPRTV-Y]{1}[0-9]{1}[0-9W]{1}[ \-]?[0-9AC-FHKNPRTV-Y]{4}$/m';
$str = 'D24 FT12
D22 TF12
D24 TF13
A65 TF12
B32 AC21
D21 3333
D6W 3333';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php