Good http header for zip file downloads

<?php // HTTP Headers for ZIP File Downloads

// set example variables
$filename = "";
$filepath = "c://tmp//zipdir//";

// http headers for zip downloads
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: public");
header("Content-Description: File Transfer");
header("Content-type: application/octet-stream");
//can also be
//header("Content-type: application/zip");
header("Content-Disposition: attachment; filename=\"".$filename."\""); 
//note: filename is the name that will be downloaded
header("Content-Transfer-Encoding: binary"); 
header("Content-Length: ".filesize($filepath.$filename)); 
@readfile($filepath.$filename); ?>