This extension is great! Very convenient.

I use it all the time and the Firefox extension is a plus to this free service.

新着メールお知らせ拡張機能はこちら (for Firefox)の通知音が消えました。
サウンドやポップアップの有無、音量、音の種類などを変更できます。が出来なくなっています

This extension is great! Very convenient. I love that I can sync/log in from different devices and don't lose addresses, can transfer email addresses, and can create unlimited number of addresses.