Item Description The WFDEXP series consists of a rugged, NEMA 4 rated cast aluminum housing. Designed for both indoor and outdoor use, the WFDEXP series operates across a wide temperature range, from 32ºF to 160ºF. Inside, two sets of SPDT (Form C) synchronized switches are enclosed in a rugged terminal block, to assure reliable performance. Reliable Performance. The WFDEXP series offers unique features that assure greater operational reliability. By housing the spring mechanism separately from the explosion environment, the sensitivity of the adjustment spring and the detector is protected at all times. Adding to the WFDEXP’s reliability is its sealed retard mechanism, which prevents contamination by dust and dirt when the cover is removed. Simplified Operation. Like all System Sensor waterflow detectors, the WFDEXP series is designed to ease installation. With its visible switch activation, the WFDEXP’s retard timing can be verified, even during noisy conditions. Features Pipe Size: 6" Pipe Schedule: 10 through 40 Conduit Entrances: Two openings for 1/2" conduit UL Pressure Rating: 450 PSI Triggering Threshold Bandwidth Flow Rate: 4-10 GPM Maximum Surge: 18 FPS Enclosure Rating: UL NEMA 4 Operating Temperature Range: 32°F to 120°F (0° to 49°C) Contact Ratings: Two sets of SPDT (Form C); 10.0A @ 125/250VAC; 2.5A @ 24VDC Overall Dimensions: 6"H x 9"L x 6.5"W Hazardous Location Classifications: Class I, Div 1, Groups B,C,D; Class II, Div 1, Groups E,F,G; Class III, Div 1 - See more at: http://www.alldataresource.com/System-Sensor-WFD60EXP-Explosion-Proof-Waterflow-Detector-For-Use-With-6-Pipe_p_205293.html#sthash.3JStTKWO.dpuf The WFD60EXP is an explosion-proof waterflow detector for use with 6" pipe. The detector has the following features: Designed and approved to operate in hazardous locations NEMA 4 enclosure rating Sensitivity-setting spring mechanism located outside of explosion environment Sealed retard mechanism Visual switch activation Synchronized activation circuit Field-replaceable terminal block and retard mechanism Only one conduit entrance required for hook-up