This paper deals with the Nucleus C124R (CS) (Contour) cochlear Implant: its characteristics, differences compared with the previous generation of devices, the perimodiolar electrode, and the surgical technique used for safe insertion. We also discuss the rationale behind perimodiolar electrodes in general, as well as the results of laboratory studies validating the design and safety of this particular electrode array. The differences in surgical technique between this device and prior Nucleus cochlear implants are as follows: the incision and the size of the well, or recess, for the electronics are smaller; the cochleostomy is larger; the posterior portion is placed in a subpericranial pocket, not tied down, before electrode insertion; and the insertion process itself is quite different, due to the nature of the electrode, its size, shape, and stylet. The technique described is that used by one experienced cochlear implant center, and reflect the authors' practice. Clearly, there are other possible variations on this theme, which may be equally satisfactory in other hands. Most surgeons find this device to be easier to place than previous generations: complications to date have been uncommon.