The mug keeps coffee warm but the app doesn't work at all.  Keep having to reestablish the bluetooth  connection.  Then the app really doesn't do anything.  Look at your ratings 1.4 stars out of 5 - something is wrong.  I use an Android phone maybe this app only works on Apple phones.  In any case, someone should rewrite this app or just get rid of it.  Really a shame that a good product is linked to such a useless app.