Yea you can take a PT3 and
buy the aerotank base and you have an Aerotank. But I'm not impressed
buy the aerotank mega heads. I rebuild my heads and damned if when i opened one up found two
coils in parallel physically just like the PT3 heads except they are harder to rebuild than the Pt3 head. I've got the Aerotank Giant. Love it. The rest are converted pt3's. OH the newer aerotank base for the PTs and up are better they are not threaded but rotate.