"Of course we haven't discussed the outer head yet. Some great ways of training this part of the biceps are hammer curls, alternate hammer curls and French bar curls. In all three your hands should be in a hammer grip"
I know what a french press is, but that is for the triceps and this article is speaking of bicep exercises. The only thing I could think of where you could put your hands in a hammer grip would be that diamon-shaped barbell that people usually use for shrugs.
there is a smaller diamond shaped bar similar to the trap bar, that is what he refers to i believe. only seen one of them at the gyms i've trained at, and never thought to use it, since it had been rewelded from a break recently it seemed.