Class I, Division 1, Groups B, C and D, Explosion Proof. Heat Trace Mounted Emergency Signaling System. Indoor and Outdoor Installation. NEMA 4X Rated. For Use With Drench Shower or Combination Units. Double Pole Double Throw (DPDT) Flow Switch in Brass Construction, 1-1/4" NPT Supply. Remote Location Hookup Possible via Contacts in Flow Switch and/or On Control Board. Automatic, Audible, and Visual Alarm. Minimum 2.4 GPM Flow Required. 3 and 6 Foot Cord Supplied for Connections to Flow Switch and Power Supply. Universal Voltage: 90-264 AC, 50-60 Hz. Amber Signal Light and Piezo Fast Beep Horn Sound Activate When Fixture is Used. Central Control Board Powers All Options and Runs on Safe 24 V System. UL Listed.