How to read any Message and be undetected - Hide seen mark

Most of the times you don't want others to know that you have read their messages. But

 Facebook features of seen messages restricts you from doing this. I will be showing you 

how you can read any message and be un detected.

•  Download and Install Facebook Unseen Add-on

• It is available for both Chrome and Firefox browsers

• You can easily be unseen even after reading messages