When your Sealand/Dometic marine toilet is not holding water or flushing properly, you may need to replace your flush ball and shaft. This ball and shaft kit with spring cartridge (385318162) is compatible with select Dometic/Sealand toilets and will help your toilet get a smoother flush. When replacing ball and shaft, consider replacing the bowl seal as well to ensure there is a water-tight vacuum seal on your marine toilet unit. Both components tend to wear at the same rate. Check part numbers to secure a proper fit.