The Dalek Leader is easily identified as being all black in colour. In the Exterminate! game he is a unique figure. Note that I painted the 52 sensor globes around his lower body and the two waistbands in gloss black paint. He is one of the plastic multi-part models and I gently bent his eyestalk, sucker arm and exterminator weapon to reposition them.
The black headed Dalek is a member of the elite Imperial Guard. Whilst they are also a unique choice in the Exterminate! game, you are allowed to field three of them as a single unit. As you will see below, this is what I have done.
Finally, we come to the standard patrol Dalek and the only limit to how many of them you can field is the points total you have decided on for your force. They are cheap, but very tough and hard to kill. I currently have 20 of them.