Protect your equipment from surges traveling through network cabling with the 4220 surge suppressor. The 4220 uses high energy metal oxide varistors (MOVs) and a double network of ultra-fast diodes and silicon avalanche diodes to protect against a wide range of potentially damaging surges, even from lightning. DIN rail mounting makes installation a snap. The 4220 has dual RJ45 connectors on each end.