2 way conversation, distance 200m, power 1.5v x 4 AA batteries or 220v AC, easy installation, 6 month warranty 1pair wired intercom

3 way intercom, No call charges No monthly rental Easy  installation, distance 200m 4 wire parallel cabling, 220v power, 6 month warranty

4 way intercom, No call chargers No monthly rental Easy installation, distance 200m 4 wire parallel cabling, operating  power 220v, 6 month warranty