The user fires an energy wave from their hand, specifically from their Energy Absorption pads.
In Dragon Ball GT, back on Earth after being released from Hell along with many other villains, Android 19 uses the technique along with Pui Pui who uses an identical blast as part of their Villainous Carnage team attack in order to cause havoc in the city.
Video Game Appearances
Photon Wave was named in the Budokai series, Dragon Ball Heroes and Dragon Ball Z: Dokkan Battle, where it appears as one of the Androids' most powerful attacks; Android 19's version is called Photon Shot (フォトンシュート).
In the Supersonic Warriors series, when he performs the Photon Wave, Android 20 moves his hand in an arc, creating a crescent shaped explosion. In the first Dragon Ball Z: Supersonic Warriors, Android 20 uses a weak Photon Wave version under the name Energy Blast, and a powerful version under the name Super Energy Blast. Photon Wave can also be used in Dragon Ball Z 2: Super Battle. This technique appears fired with both hands as Android 19 and Android 20's Super Attacks under the name Full Power Energy Cannon in Dragon Ball Z: Battle of Z.
It is called Syphon of Energy in the Dragon Ball Collectible Card Game, where it is blue instead of purple.