SalesHandy
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SalesHandy email tracking tool for Gmail allows you to know whether your sent emails have been read or not.
ActiveInbox for Gmail
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ActiveInbox for Gmail is an email management software for Gmail.
Gmelius
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Gmelius is a free browser extension available for Google Chrome, Mozilla Firefox and Opera that customizes the look and feel.
Followup.cc
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FollowUp for email is a lightweight productivity suite that keeps your conversations and tasks from slipping through the cracks.
Compare Boomerang with alternatives
Compare SalesHandy and Boomerang and decide which is most suitable for you.
Compare ActiveInbox for Gmail and Boomerang and decide which is most suitable for you.
Compare Followup.cc and Boomerang and decide which is most suitable for you.