Helipal is a dji dealer and it should be a DJI part being there are no exact match generics for the ESC's that I am aware of. so it should be the oem. and it wont be one you have to jury rig to make it fit or work. as long as its the right part number.
Tho I forget the brand of the top of my head that makes the esc's for DJI I want to say its Turnigy. But its really only a dji part by name cause dji don't make there own esc.