The Optimus Red range of sound level meters are designed for occupational noise surveys, providing all the measurements you need to meet the requirements of the regulations.
Many regulations require the use of an integrating sound level meter that can provide you with measurement of LAeq or Lavg and Lpeak. The Optimus Red range of meters provide this.
All three models meet the requirements of the regulations. For occasional use, the basic integrating meter is certainly adequate. If you don't want to write down the results, or have lots of measurements to make then the data logging meter will make life much easier. Finally, for very high noise levels a more detailed analysis may be beneficial. The octave band meter is the best when selecting the most suitable hearing protectors for this type of environment.