Hi Cosmo...I have to say, I really don't know. These were made by the company for us in Holland and if you were a pilot, you got "the best filters" as I was told. I would suggest that if you are interested in a pair of these that you contact an Elacin representative and explain your concerns and I am sure that they will be able to advise you accordingly.
As for what you can hear, it is absolutely fine. You will hear your colleague fart on the flightdeck but the loud fatiguing noise is removed (of the aeroplane that is!). You can certainly hear all ambient sounds, such as warnings and Cabin Crew talking to you- no need to remove the earplug When you speak it does seem to you to be a bit muffled but you get used to it.
I would advise going for a set. What price do you put on your hearing?