[reformed]

The first one is a waste if you still have a catalytic converter. (and who knows if it would work anyway)
The second one is only for HHO generator cars. (and again, probably as pointless as these HHO generators seem to be)
The third one just doesn't have a good explaination as to how or why it works.. and with a claim of +20%, it should be explained in detail.

It seem to me like this guy is one of many, who have jumped on the bandwagon of fooling the unsuspecting with claims of false mileage increases from bogus products in this time of rising gas prices.