Keep your eyes on what your students are doing behind you. Monitor student behavior and classroom safety. Place the magnetic mirror at the top of your whiteboard. When you are writing on your board, simply glance up to check on your students. Adjustable up and down and left to right. Features clear, wide-angle mirror; firm magnetic hold, non-slip base (5.5" ), and hanger holes for mounting on non-magnetic surfaces too. Instructions included. Measures 18" W x 3.5" H x 3.5" D.