MARINE "BLACK BOX" DIGITAL MEDIA RECEIVER WITH WATERTIGHT COMMANDER CMS4 Design Engineered to Withstand Water and Salt Water and salt can be a marine source unit's worst nightmare. Our CMS4 source unit is IP66 tested to provide you the very best water intrusion and salt protection in its class. It also meets or exceeds ASTM MARINE "BLACK BOX" DIGITAL MEDIA RECEIVER WITH WATERTIGHT COMMANDER CMS4 Design Engineered to Withstand Water and Salt Water and salt can be a marine source unit's worst nightmare. Our CMS4 source unit is IP66 tested to provide you the very best water intrusion and salt protection in its class. It also meets or exceeds ASTM