Genuine Oase replacement impeller rotor for Aquamax 3500E 2019  pond pump
Oase part number 71798
Impellor very similar to the photo but the magnet is slimmer.
magnet diameter is 19mm
magnet and white plastic ends 43mm overall
From shft end to outside of impeler blades is 81 mm
White impeller disc is slightly over 46 mm O/D
Black disc behind impeller is 54 mm