- Put spread premium is $7, if QQQ drops to 490, you will only incur 75% of the actual loss.
- If QQQ continue to drop, you can roll this down to next level, something like 495-465, and again, you will incur maybe 50-70% of the loss from 495 to 465.
All in all, when direction is right, you can protect your porfolio such that 50-70% of the drawdown is avoided.
In real life, stock hardly drop from 520 to 465 without any bounce, so there are other ways to gain more protection.