The Emperor Aquatics Smart UV Sterilizer Service Kit includes all the gaskets and o-rings for the Emperor Aquatics Smart 25 Watt UV Sterilizer, Emperor Aquatics Smart 40 Watt UV Sterilizer and Emperor Aquatics Smart 65 Watt UV Sterilizer. This Kit WILL NOT work for the Smart Lite UV Sterilizer. Those Sterilizers have a 2" body. This Service Kit is also NOT meant for the high output Emperor UV Sterilizers. NOTE: they recently changed the Quartz Sleeve Gasket. It no longer needs to have the small o-ring next to it. You may want to look at the New Emperor UV Exploded View Diagram to see the placement of the o-rings.