A Dalekoat was a protective exosuit that could be worn by a Dalek around their actual casing to protect them from dangers incurred when doing dangerous engineering work. The Dalekoat included a single, large claw-like appendage located squarely in its centre.
The Chief Scientist wore a "special" protective Dalekoat while plugging large cables into the Dalek Emperor's new casing in the Great Hall of the Dalek City. This Dalekoat was green, with a light blue base. It was documented, along with the Emperor's new casing itself, in a report sent back to Earth by a Space Security Service investigator. (COMIC: The Secret of the Emperor)