I exchanged the piston air valve cap of my vehicle for a big bore piston air valve cap.
The previous one was silver and sober; I chose red so as to fit to my vehicle body color this time.
The more eye-catching, the better; a colored cap looks more attractive and exceptional.
In addition, a normal type looks just a cylinder, while a big bore type looks like a piston properly.
A big bore cap was larger than a normal one, so the head looked oversize to me. That was why I subtracted 1 and put 4 stars. I recommend this product to a witty person.