A cap for coupling to a medical adapter may include a housing with a closed top end and an open bottom end with legs that extend from the housing away from the bottom end. Members may extend from an inner surface of the legs to engage and secure the cap to a medical adapter or an insert configured to mate with a medical adapter. A cap may include angular ridges between a cap housing and an insert to permit rotation of the cap in single direction and prevent removal of the cap from a medical adapter. A cap may include hinged legs to permit the cap to be secured to a medical adapter by rotating the legs toward each other until a portion of a collar on each leg may be matingly joined around the medical adapter.
