The Sentry MK2 is a cut off limiter, it removes the mains power to any equipment supplied through the contactor.
 
Features:
 
With an adjustable measuring range from 85 to 125db every possible eventuality can be dealt with.
There are 4 weighting curves linear, C, A and bass there are also two different level settings.
A large led display shows the operator how loud the noise and is visible from a distance.
An internal or external microphone can be used to measure the noise level.