A revitalising unit was a piece of Cyber-technology that allowed Cybermen to recharge their systems when their power levels ran low. It consisted of two components. The first resembled a large, rectangular sarcophagus with an emblem mimicking the Cybermen's facial features on front. Inside was a cast big enough to accommodate the larger Cyber-Controller. The door was hinged at the right and opened outwards. The second component was a projection device, essentially an obelisk about seven to eight feet high with a trident shaped section on top. This section could pivot up and down and bombard the first component with energy that revitalised the occupant.
Kaftan attempted to kill Victoria Waterfield with this machine, but was stopped when the Second Doctor intervened. Later the Cyber-controller entered the revitalising unit when it became too weak. The Doctor attempted to trap the controller inside the unit, but it smashed its way out. (TV: The Tomb of the Cybermen)