Abstract: The present invention relates to an apparatus that controllably allows the relative rotation between structures, such as a gimbal and a structure to which it is mounted. According to one aspect, the apparatus includes a twist capsule assembly with internal stop mechanisms that controllably prevents the amount of clockwise and counterclockwise rotation with respect to a rotation axis. According to another aspect of the invention, by limiting the amount of relative rotation, other means of communicating power and signals between the structures can be used, thus avoiding or reducing the limitations imposed by conventional slip ring assemblies. According to yet another aspect, the invention includes techniques and structures for allowing conventionally shielded cables and wires to be used in place of slip rings, while allowing for rotation between structures, thus even further improving the communication of power and signals between structures.