7.2.5.2. The following equipment can be used:
Lights;
The colours of the lights shall be red, yellow and green in that order with
the red at the top. The lights shall be synchronized and at no time shall two
different colours be on at the same time. In Championships, the lights shall
be linked with the acoustic equipment so that the first sound of the acoustic
equipment is simultaneous with the light turning red and the digital clock
reaching zero.
Digital Clocks;
When timing is controlled by the use of digital clocks the figures on the
clock shall be a minimum of 20cm in height and shall be able to be clearly
read at a distance of 100m. They shall be able to be stopped and reset very
quickly as and when required. The clock shall function on a countdown
principle. All other requirements shall be the same as for lights.
When digital clocks are used, lights are not mandatory.
If both systems are used they must be synchronised. If there is a discrepancy
the digital clock takes precedence.
The visual signals are to be placed on both sides of the field and, if
necessary, in a clear lane between target butts, at any distance shorter than
30m, so they are visible to all athletes, both left and right-handed, on the
shooting line;
Match play indicators;
When shooting the alternating match play there shall be separate green/red
lights, countdown clocks, or other visual signals for each athlete to
indicate whose turn it is to shoot.
Emergency Equipment;
When the time limit is controlled by electrical equipment, plates, flags or
other manual indicators shall be available in case the other equipment fails.
When the time limit is controlled manually by means of plates, these are a
minimum of 120cm by 80cm in size. They shall be securely mounted to resist
any wind and shall be easy to turn quickly to show either side. One side of
each plate shall be green and the reverse side of each plate shall be yellow.
Lights or digital clocks and emergency equipment are mandatory for
International Events.