Emergency Telephone Color Silver Includes Emergency Push Button Material Stainless Steel Mounting Location Surface Operating Voltage 24V DC Product Type Emergency Call Boxes Features These Telephones Will Operate from an External DC Power Source which is the Only Wiring Required for Operation Maximum Operating Temperature 131 Degrees F Minimum Operating Temperature -4 Degrees F Overall Depth 2 3/8 in Overall Height 12 in Overall Width 10 in Standards FCC CRF 47 Part 15 UL/CSA