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.