Unless you are planning on photographing an animal or bird most users find that sound is the easiest and most reliable method of triggering as there is no alignment of a laser beam involved.
However, sometimes the sound that you need to trigger from may not be sufficient for the standard microphone to detect.
The hi-sensitivity microphone plugs into the Mic input of the VersaTrigger and gives approximately 80 times more gain than the standard microphone, no batteries are required as it is powered from the VersaTrigger control unit.
Typical uses for the hi-sensitivity microphone are:
Detecting a small object falling onto a surface without having the microphone in-shot
Detecting water droplets falling on water (water drop photography - not water drop collision)
Detecting the sound of a projectile flying through the air