This is a particularly interesting segment of the Montañas Negras (Black Mountains)
loop. The doubletrack travels through areas with almost no vegetation and you are left in an apparent moonscape of volcanic black lava rock particularly as you reach the end of this segment at its intersection with TF-38.
The downside to this is it means that it can be quite hot as there is no protection from the sun. The lava rock that forms this moonscape is the result of an eruption in 1798 from vents on the west side of el Teide.