A metal bar underneath the seat is moved up and down with quick release button. (carseat.se)
With one quick release button you can fold or unfold it easily but it is not a one hand fold stroller unlike some other stroller, you need to use two hands to fold. (bestbabydollstrollerreviews.com)
Arsenal need strength and pace along with quick release of the ball in the middle of the park. (justarsenal.com)