It also came with the 08 set, it became available as a single accessory in the Netherlands around the time the parallel guides were introduced.
article number: 496450
You can mount this part in an adjustable chuck, and then click the centrotec chuck on.
But the longer bits can also be used in regular bitholders (not the ball detent chucks like on impactdrivers); you don't get the extra centrotec "guidance", but I have used them together with the really long bitholder of the centrotec set aswell.