With every great attribute that the Low Profile 200 strobe light provides, the A/V 400 enhances safety with an audible warning as well. This audio alert is a slow beep (play it below) that emits an audible alert where needed. The foundation of our A/V strobe light unit is a rugged cast aluminum base, with four holes for easy mounting to almost any surface. Four self-tapping screws and plastic shims are included with every unit.