PET perform mould has different interchangeable choice; mould maker can make the perform weight interchangeable, neck screw interchangeable.
Perform neck interchangeable means change the neck screw inserts. We can make different screw on the neck insert. It only needs to change this insert on the PET preform mould to making the product with different neck screw.
Most customer don’t need large output, so they ask for interchangeable perform mould, it can reduce his cost from mould building. But if your output is very large, it is better to make two mould.