Fits the older smooth body Emerson 56 frame (6.1") pumps only. There is an identical part to this that was used with Magnetek motors which was 56 frame (6.3")
This unit includes the housing the face plate the face plate o-ring the 2.5hp impeller and the ceramic seal kit. This unit also includes a built in bleed screw.
The space between the impeller plates is 10mm