ウェブ上の Google Play でアイテムを購入し、すぐに Android 搭載端末やタブレットでお楽しみいただけます。わずらわしい同期設定は不要です。
Sync My Mail app allows you to set the time(s) to download your new email from all GMAIL accounts set in your phone.
Main intention is to save battery life. You can disabled the automatic synchronization settings (which are constantly checking for new incoming email and lower your battery lifetime), and your mail will be checked at a user given time.