PVC union, 50mm internal diameter, with a rubber band.
For the proper installation of the ΗΑ350 & ΗΑ460 pumps, you have to order a set of 92020M and 92015M fittings.
Example: for 1 unit HA350 you are going to need 1 x union-tee (92020M) & 1 x union (92015M) or 2 x union (92015M).