Lifegard Aquatics Pro-MAX 120 Watt Amalgam Bulb 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 which counts down the number of days until you need to replace the bulb. Maximum Operating Pressure 30 PSI.