How do I operate and how much should I tighten the screw-down crown?

Many watches that are highly water-resistant have screw-down crowns,such as Rolex replica,Porsche Design replica,Richard Mille replica,Zenith replica and Hublot replica.Essentially, the crown of the watch (the knob on the side used to wind and set the watch) screws in place like a tiny bottle cap to make sure that part of the watch is extra water-resistant.
To open the crown, simply turn the crown anti-clockwise to unscrew it (takes about 4 or 5 turns). To close it back, push it in while turning clockwise. Do not close it real tight, just with mildly firm finger pressure. It is the threading that provides water-tightness, so over tightening does nothing to increase the water protection and can overstress the metal, eventually damaging it and ruining the water protection of the crown.
A few diving watches also have a "helium relief valve." If yours does, check that it is closed similarly.
Once the crown is unscrewed and in the "neutral" position, the crown operates like any normal watches,such as Longines replica,Tudor replica,Romain Jerome replica and Tag Heuer replica.