Top End Gasket Kit Sea-Doo 720 – 6600. Fits Sea-Doo720 engines. Head Cover O-Ring. Spark Plug O-Ring (2). Cylinder O-Ring (2). Water Jacket O-Ring (2). Base Gasket (.020/0.5mm). Carb Gasket 38mm (2). Exhaust Gasket (2). Headpipe Gasket.