These federal signal explosion proof vibrating horns are constructed for safe use in hazardous environments. They are enclosed in heavy duty copper-free cast aluminum housings tapped for 3 /4 in conduit. Federal signal models 31X and 41X are corrosion-resistant vibrating horns with stainless steel diaphragms. Model 41X is available in 24 VDC. The model 31X is available in 120 VAC and 240VAC and features an internal volume control. The 31X and 41X models are UL and cUL listed for class I, division 1, groups C and D, class II, division 1, groups E, F and G and class III. Both are CSA (Canadian standards Association) certified. A 5 min duty cycle applies to both models.