Desco 60640 Chargebuster 24" Overhead Ionizer3 Blade Fans with Steady State DC Ionization For 2 X 4 Coverage Area Specially designed fan modules create better coverage (2 x 4), consistent offset voltage (balance) 10 Volts, and superior discharge times(<3 seconds) tested per ANSI ESD STM 3. 1 Auto Feedback System (Audible And Visual Alarm Through Single Tri Color LED)Unit will automatically shut down and alarm if when supply voltage drops 120 220 VAC Input Voltage Selectable Unit can be used with