What are the criteria you will adopt in selecting ear defenders ?

While doing noise surveys in industries I am seeing different types of ear defenders in use. I find that most of them do not serve the purpose and gives a false sense of protection to the user. This practice has to stop. In selecting ear defenders one should have thorough knowledge on the prevailing noise conditions, available ear defenders in the market , its usefulness and so on. Let us have a discussion on this serious issue.
Kesava Pillai

Sir
can you share knowledge about NRR !

Dear Sir,
Nice to see this post from you.
Most of the industries, do carryout a noise survey. If the results indicating that the noise level is beyond the statutory limits, either they go for Ear Plug or Ear Muff. That's it. In 90% of the Indian industries this is the practice...
Very few organizations who face an issue with Noise try to mitigate the same from it's roots by applying elimination methods/engineering controls,etc.
Looking forward to learn more on this from you...
@Sanoj - Appreciate the participation and ask question about NRR...