Abstract: An arm device comprising a universal joint, which universal joint comprises a first wrist joint, a second wrist joint and a first elbow joint wherein: each wrist joint comprises a first part, a second part and a slipring, which slipring comprises a rotor coupled to the first part and a stator coupled to the second part, which rotor is coaxially engageable with the stator and infinitely rotatable relative to the stator such that: the first part of the first wrist joint is infinitely rotatable relative to the second part of the first wrist joint about a first axis, and the first part of the second wrist joint is infinitely rotatable relative to the second part of the second wrist joint about a second axis; the first elbow joint comprises a first portion and a second portion, which first portion is rotatably engageable with the second portion about a third axis; the first wrist joint is coupled to the first elbow joint; and first elbow joint is coupled to the second wrist joint.