This 2" x 3" acrylic mirror is virtually unbreakable and weighs just 0.75 ounces.  Operates on the same principle as the glass military signal mirrors with grid and fireball targeting.  Mirror will float if dropped in water.  The scratch resistant surface is covered with a removable and replaceable non-glare vinyl sheet to prevent inadvertent flashing and provides protection.  Click here for sighting pictorials.