The body of a cock cage is a tube that holds the penis. It is attached to a ring that goes around the penis and scrotum. Some features of a penis cage may include a hole at the tip to allow for urination and vents to allow for long-term wear and cleanliness.
Chastity is a kink that can be practiced by anyone of any gender, but cock cages are only applicable to people looking to enjoy chastity while owning a penis. Chastity belts are better suited for people who have a vulva.