The double extra APO powerups consist of the following powerups:
As their names indicate, each type grants 2 extra points of a different feature, and the last one gives out the same, but for all features.
If all slots are already full, then this powerup will hand out credits in Carmageddon II. This amount is the same as the cost of buying an APO point in the current difficulty level. In Carmageddon: TDR 2000, this powerup will have no effect.