Lifegard Aquatics Pro-MAX 40 Watt UV Sterilizer in 3″ Housing – featuring a patent-pending, flow-through design with less restrictive angled inlet and outlet ports requiring less plumbing. This unique design enables easy installation of new or replacement systems as it can be positioned in multiple ways to fit any tight space. Available with 3″ housing in 25, 40, 55, 90 and 120 Watt models and 5″ housing in 55, 90 and 120 Watt sizes. Each Pro-MAX™ features a High Output UV Bulb, Internal Protective Sleeve, and UL Listed Ballast (Note: The counts down ballast only comes with amalgam UV Sterilizers 55 Watt, 90 Watt and 120 Watt). Maximum Operating Pressure 30 PSI.