Hi, Guess you can help. I need to replace the battery in my house smoke alarm (EXIT brand model 3786M2). How do I open the cover? Is it a simple anti-clockwise twist of the cover or I need to poke a screw driver to loosen and slide the cover out. I am aware that I need to switch off all power connections to the lighting and smoke alarms before trying to open the cover. Any suggestion will be helpful. Asit