The Emperor Aquatics Smart HO UV Sterilizer Service Kit includes all the gaskets and o-rings for the Emperor Aquatics Smart HO 50 Watt UV Sterilizer, Emperor Aquatics Smart HO 80 Watt UV Sterilizer, and Emperor Aquatics Smart HO 120 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 25W, 40W & 65W Emperor UV Sterilizers. NOTE: they 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.