Once downloaded firmware update, can it be used to restore ipad later?

After a lot of tries and a lot of "timed out errors", my iOS firmware update download is finally in progress. But by the time it finishes, I won't have the time to restore the iPad then and there. So, once the download completes , can I turn off iTunes and use the downloaded update to restore the iPad in recovery mode sometime later? Or It would ask me to download again?