Can type filters are usually applied as fine filters and coarse filters in multistage filtration systems, and there are often filters used with characteristic drain plugs inside the separator. Water generally does not dissolve in fuel, but remains as drops or emulsion causing corrosion process intensification of metal parts in fuel system. Water is removed from fuel using sedimentation effect (gravitation drops settling in decanters) and coalescence - water drops separation in fuel flow through filter medium. These filters are designed similarly as can type oil filters, however, they do not have any inner valves. The filter replacement process is also similar and means only unscrewing the used filter and tightening the new one. Also as in the case of spin- on oil filters, used filters disposal is expensive and this model is widely replaced by "ECO" cartidges.