Compact Steel Ringdown Telephone Overall Depth 2 1/4 in Overall Height 9 in Overall Width 5 in Volume Control Yes Indoor/Outdoor Usage Indoor Standards FCC TCB Number of Lines 1 Mounting Location Wall Enclosure Material Steel Enclosure Rating NEMA 3R Includes Enclosure Yes Facility Type Commercial Maximum Operating Temperature 176 Degrees F Minimum Operating Temperature -76 Degrees F Color Gray Resistance Properties Corrosion Resistant Features Electret Noise Reducing Microphone