THEIR OWNER ONLY BUYS PREMIUM QUALITY SLAVES
...and he never regrets acquiring the identicl twins we see here, in spite of the enormous cost that family-related slaves fetch. He enjoys dressing them in similar clothing to emphasise their similarity, but particularly revels in seeing them together in the slave showers after work.... they then go to his "playroom" with no need to dress, and he enjoys seeing how having their hair, body hair and pubes all clipped and trimmed alike makes them so very much alike.
He quickly discovered that, compared to two non-related but similar-looking, the high cost of these was justified. In the past, he normally had to spend a couple of months removing any inhibitlions non-related slaves had, and the necessary use of the whip to "encourage" them was somewhat distressing (for the slaves, that is, not him!). Twins are used to growing up together and naturally go through puberty simultaneously, and learn from that early stage how to use each other's bodies.