Slightly different style and ready to go :)
$file = 'folder/' . $name;
if (! file) {
die('file not found'); //Or do something
} else {
// Set headers
header("Cache-Control: public");
header("Content-Description: File Transfer");
header("Content-Disposition: attachment; filename=$file");
header("Content-Type: application/zip");
header("Content-Transfer-Encoding: binary");
// Read the file from disk
readfile($file);
}