For use with 2 satelllite lines 1 cable TV or antenna line and 1 telephone lineDesigned to protect standard phone lines connected to computer modems telephones pay-per-view etc25V clamping level for satellite and 1.4V clamping for cable TV linesBi-directional protection for both cable and satelliteFor use with PM8-EX M4-EX M8-EX familiesBackwards compatible with the Tower Max family