The BSWA 309 is a digital sound level meter that complies with the IEC61672 Class. The use of high precision 24Bits AD converter makes the instrument to bea ideal choose for performing many kinds of measurement tasks, for example in environmental noise, vehicle noise and industrial application. A main interface can display most useful information of the instrument states and basic noise result. In addition, there is a three profiles interface display independently result that measured in parallel. All profiles can be defined different filters (A, C, Z) and detector time constants (Impulse, Fast and Slow).