Description Product Reviews Safety-assured for explosive atmospheres! Weather-Resistant Solid Metal Housing Built-In Amplifier & Volume Control (One-Way Speakers Only) Includes V-1092 Volume Control UL Listed For Use In: Class I, Groups C & D Gas Atmospheres -20 Valcom Power Units Valcom Power Units Every Valcom product is marked with either a positive, negative or neutral power unit. Simply add up the negative power units and then purchase a power supply with a greater value than the total power consumption of the system. If you have extra power units you can add speakers to the system at a later date, extra power is OK lower power will cause a performance problem on your paging system. One Valcom power unit = 50 mA, -24 Vdc 0 Reviews Hide Reviews Product Reviews