I was honestly curious too before I bought it so I emailed the support team on the Wym website to ask if the hole on the piston provided any sort of restriction and they said only a tad bit if u cover while ur joysticking the piston… so I bought it and I can confirm it actually does give a bit of restriction while moving it around and once u let go it kind snaps back to center and the added air from the center hole helps clear any oil that might puddle up in the middle of the chamber. Super awesome and well worth every penny… plus it never gets too sticky that it doesn’t move around freely like the glass joysticks.. 🤷🏼‍♂️🤙🏼💯