Anything that says it's a "booster", is used for just that. Boosting airflow over larger distances. They don't move an adequate amount of air to cool an HPS as efficiently as a "can fan" or an exhaust fan. Any fan you are looking at should be rated by the volume of air it moves, usually measured in Cubic Feet per Minute, or CFM.

CAN-FAN 4 INCH HO 178 CFM INLINE FAN FREE SHIPPING - eBay (item 200290710186 end time Mar-21-09 08:59:26 PDT)

This one is just an example, there are many like it around. Have fun searching, and holla if you need....

I just looked at the fan in ur link, and I don't think they are advertising what that fan can generate. It may be sustainable for boosting up to a 240 CFM system, but I don't think it's generating 240 CFM of exhaust by itself. Hate to disappoint, but good exhaust fans aren't good because they are cheap, you definitely get what you pay for.
irydyum Reviewed by irydyum on . Do I need to vent 400 HPS Cool Tube in a 4'X4' space? I have a 4'x4' area, with 1' section for veg, and a 3'x3' section for bloom roughly. I am going to use cfl's for veg, so heat shouldn't be an issue there. The bloom side will have a 400w HPS in a Cool Tube. Do I need a fan to blow through the tube, and do I need to exhaust the hot air through a vent to the outside. The space gets warm, not hot in the summer, and cooler than the rest of the house in winter. I would apreciate your input and ideas. I am not much of a DIYer. Easy, simple, Rating: 5