Well, it's a trans double bond because these two groups basically .2 opposites in the opposite side. And so what that means is it's a trans delta four. Basically to describe the stereo chemistry of the double bond, all we have to add is a CIS or trans to the beginning of that double bond. So in this case it's trans delta four, in this case it's trans delta ten. But we can also have CIS. In fact, the cysts are the more common ones inside our body.