It's simple. It's tattooing the scalp to make it appear as though there is stubble growing. It makes it look like a guy really has hair but has decided to shave it off and there is just stubble coming in. It's a stretch. And if a guy then later decides to go to a hair system the 'stubble' will show through the base. Gotta think twice about going this route.
John

It looks real from a certain distance but I always thought if someone touched that scalp would be a weird moment.