This red-dot sight can operate without a battery, using a solar cell on top of the unit that acts as an additional power source.
To shoot a red dot in bullseye well, you have to choose: focus either on the target or on the dot. You can’t do both, or go back and forth between the two. Here are techniques from Brian Zins to properly aim a pistol red dot sight
Aiming the red dot sight, forming a shot process and how to handle anticipation.
I have found that many shooters think entirely too much. This is not rocket science, because if it were, I would not be a shooter. Hence, I am not smart enough to shoot badly. When Erich Bujung was the Olympic Pistol Team coach, he always said, “No stinking thinking. The mind is a terrible thing to waste and in Bullseye on the firing line, the mind is just a terrible thing.”