<P> A handle is attached by a bolt running vertically through a hole in the centre of the stone . The handle allows the stone to be gripped and rotated upon release ; on properly prepared ice the rotation will bend ( curl ) the path of the stone in the direction in which the front edge of the stone is turning , especially as the stone slows . Handles are coloured to identify each team , two popular colours in major tournaments being red and yellow . In competition , an electronic handle known as the eye on the hog may be fitted to detect hog line violations . This electronically detects whether the thrower 's hand is in contact with the handle as it passes the hog line and indicates a violation by lights at the base of the handle . The eye on the hog eliminates human error and the need for hog line officials . It is mandatory in high - level national and international competition , but its cost , around US $ 650 each , currently puts it beyond the reach of most club curling . </P>
<P> A handle is attached by a bolt running vertically through a hole in the centre of the stone . The handle allows the stone to be gripped and rotated upon release ; on properly prepared ice the rotation will bend ( curl ) the path of the stone in the direction in which the front edge of the stone is turning , especially as the stone slows . Handles are coloured to identify each team , two popular colours in major tournaments being red and yellow . In competition , an electronic handle known as the eye on the hog may be fitted to detect hog line violations . This electronically detects whether the thrower 's hand is in contact with the handle as it passes the hog line and indicates a violation by lights at the base of the handle . The eye on the hog eliminates human error and the need for hog line officials . It is mandatory in high - level national and international competition , but its cost , around US $ 650 each , currently puts it beyond the reach of most club curling . </P>
how much does a rock cost in curling
how much does a rock cost in curling
around US $ 650 each
around US $ 650 each