The Trojan 660003-R is an ultraviolet (UV) water filter which is:
The Trojan UV Max Pro 50 - Ultraviolet Filter System contains a 200 watt UV light that disinfects your home's water. This Trojan UV system is more effective than chlorine against a broader range of organisms. This UV light filter contains a stainless steel water chamber and has a safety cap. This UV disinfection system has 2 inch Male Pipe Thread (MPT) inlet/outlet connections, and has a maximum flow rate of 50 gallons per minute (gpm).
The Trojan 660003-R specifications: