Before the bow can be used it must be tensioned. This is done by turning the frog screw clockwise until the desired amount of tension is achieved. The correct amount of tension depends on the preference of the individual player. As a guideline, when the hair is tightened correctly, the space between the hair and the bow at the middle of the bow, should be about the same as the thickness of the bow.
 

Correct

When the bow is at the correct tension,
there should still be an arch in the wooden stick.

Incorrect

An over tightened bow will have a reverse arch in the wooden stick.