This rotor fits the Rena Flow 4000 pump UL MOD# M3(S). In addition, it will also fit the Pond Care 850 item 705K and Pond Care 1250 item 705L. The assembly consists of ceramic shaft, bearing/bushing and rotor/impeller. *Please note we have no more of the original rotors for the Pond Care 1250 which was discontinued over 10 years ago. If you use this rotor in a Pond Care 1250 you will get lower flow probably as much as 20% lower but max pumping height should still be over 11ft.