The CIS4/45 is a 2-gang, vandal resistant call-in station with integral speaker/microphone comprised of a - 2.5" square frame loudspeaker with a 2.35 oz. ceramic magnet, 45 Ohm impedance, and a moisture resistant cone - a momentary (normally open) push-to-call button. Three (3) interwoven, steel security screens are mounted between the faceplate and loudspeaker. Tamper resistant, 6-32 x 1" 'pin-in-torx' hardware included.