HANDSFREE DOORBOX-STAIN STEEL Viking Electronics W-3000 Viking Weather Resistant Speaker Unit, Vandal resistant, 14 gauge stainless steel faceplate, Microphone volume adjustment POT, 24 volt talk battery, 20 Hz ring generator, -15°F to 130°F Extended operating temperature range, 4-pin screw terminal strip Connections, Yellow call progress/ night light LED (W 3000 W3000)