You did not post the link, but I an guessing it is the tablesaw that drops the blade when a finger (or other "meat" product) is in contact with the blade. Name is Saw Stop. Could be a great item for schools and such but too expensive for my wallet. $4017 for a single phase, 5 HP tablesaw. Once tripped, there is more costs since the blade is ruined and the mechanism is required to be replaced. Just my opinion.
if you have never made a mistake, you probably haven't done much.