Cell charges his energy wave and Frieza charges his finger beam, and they then fire the blasts together at their opponent.
They prepare this attack in Dragon Ball GT, but do not fire it: after successfully freezing Goku in Hell, Frieza and Cell begin to charge the Dual Tech in order to finish him off, but stop after the ice that Goku is in starts to melt.
Video Game Appearances
The Dual Tech appears and is named in the Dragon Ball Z Collectible Card Game, where it is part of the card "Cell and Frieza's Dual Tech". It does fifteen life cards of damage. If used by Cell or Frieza with both in play, the user can discard two of their opponent's non-combat cards.