Super Buster Cannon
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Directory: Techniques → Offensive techniques → Ki → Energy beams
The Super Buster Cannon (スーパー バスター キャノン, Sūpā Basutā Kyanon ) is an enhanced version of the Buster Cannon and used by Future Trunks. Future Trunks draws his hands back down to his sides like the normal Buster Cannon, but charges more power in his hands. He then combines them together in front of him to fire a huge Buster Cannon energy wave at the opponent, inflicting a huge amount of damage.
In Dragon Ball Z: Burst Limit it is his Ultimate Attack.