These two heads can combine to create a 3rd - The "Beast" Head
Giving you 3 Levels of Shave Profile.
View this video to see how.
The name "Beast" comes from the aggressive look of the open comb top plate and higher Shave Profile that the head has. It was aptly named by Youtube Shaving Reviewer "Kit" (check out his channel here) who first discovered the combination and how well it shaves.