i would like to add some informations :
1/ melpheos compared the diameter of the inlet of some pumps, the larger diamater varies from 12mm on 1 pump to 11mm on ther other, the result is that even the plastic fittings
shipped with the pumps cant be inserted:
here is a tentative of insertion of a NPT-BSP adaptater
2/ here are the pictures of the interior an d outlet of some pumps :
3/all the blue pumps we recieved had scratches on the exterior .