did you read the other post here i copy for you part of it :
NW150: 6"x23" reaction chamber, Offlabled OR 2700 $139
CS 80: 5"x22" reaction chamber, sedra 3500 pump? $200
NW200: 8"x24.5" reaction chamber, Offlabled OR 3700 $189
CS 180: 8"x24" reaction chamber, GenX 4100? $628
In both cases...