You can use your 16-digit key to restore your authenticator app in case you've lost your phone or deleted GetEx account. Having used this key you'll be able to restore your account in your Google Authenticator app.
Links to download Google Authenticator:
App Store: https://itunes.apple.com/gb/app/google-authenticator/id388497605?mt=8
Google Play: https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2
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