This is another series of scenes from Zen Prison Studio. The dungeon-themed settings give a dark atmosphere in which quite good-looking female slaves are bound, whipped, and subjected to fucking machines. Some scenes border on horror porn. There is no actual sex. The whole set-up is reminiscent of Insex, I'd say. Most of the time, the girls are masked, but in one shorter scene (just found that one today!) the girl is unmasked, but has her face censored.