the watts for the rider listed are really a red herring. if the helmet reduces drag by X amount at Y speed, the things that are relevant are the X and the Y, not the Z power output as the rest of the rider/bike system might be assumed to remain unchanged. Give that the number posted make no sense on the Giro site, ie 1g reduction = 1w means they either need to correct their data or tel us why they are testing at 50 mph instead of 30mph(or whatever speed they are testing at , as it is not listed on the site) While Jim may be giving good insight, the giro site really looks like bad marketing spin that was not checked before uploading to the interwebs