We saved the best for last.

More accurately, we saved the most difficult for last.

It's the fourth and final round in our annual Summer Lifeguard Challenge. For the August challenge, Judge Pete Dequincy wants your team to demonstrate an in-water ventilation.

This is tough for two reasons: 1) Rescuers will have to swim far and dive deep to retrieve the submerged victim from the deep end; 2) Rescuers must give the victim two honest-to-goodness breaths using a mask. No mock breath deliveries.

Watch the video above to learn about how your performance will be judged and how to submit your video.

Deadline is August 31.