Force Save As Download On a File in PHP

<?php
$strPhyFileName = "FILE PATH HERE!!!";
$strSaveAs = "FILE NAME TO SAVE AS"; 
$size = filesize($strPhyFileName);
header("Content-Type: application/download"); 
header("Content-Length: $size"); 
header("Content-Disposition: attachment; filename=".$strSaveAs); 
header("Content-Transfer-Encoding: binary"); 
$fh = fopen($strPhyFileName, "r"); 
fpassthru($fh);
?>