"Complete Wave 7" is an objective in the sidequest Hyperion Slaughter: Round 5 in Borderlands 2
The final wave, thy do not hold back. A Badass Constructor with Badass Surveyors drop immediately. They are supported by a second Constructor on the Western platform. The turrets are redeployed as well. This is not an easy fight.
The Constructors will definitely begin assembling things before you can take them both down. This just means you can press on through the weaker Loaders that are thrown at you. THey are very helpful as Second Wind material as you take on the Badass Constructor and a lot easier to hit than the Surveyors. Still, focus on the Constructors and Surveyors equally here. It will make your life a lot easier. The sooner the Surveyors or Constructors go down, the less difficult the fight will be. Defeat these forces and the Hyperion Slaughter is cleared.