I am so impressed with these goggles. Aside from the simplicity factor (one button on/off, they accurately auto-detect everything from there), they have immediately improved my form and times. In reviewing the head position video from my first swim with these it was clear my head is too high and moves too much. For the next swim with them I focused on keeping my head down and dropped seconds immediately. Even warmups were distinctly faster with no change in perceived effort - I literally muttered aloud “what just happened?” Wrapping the workout with some short sprints had me giggling at posted times. Can’t wait for my next swim in these goggles!