I can't locate any information for the NRR of these earplugs. Those with T should be cautious about placing their trust in the attenuation capacity of any product that does not list the NNR over a range of frequencies, IMHO.
check out EarPeaces website. I think they are around 20 db (maybe 19 or so). im not sure where I got that but I remember wanting to order them and then realizing they are not very strong. http://www.earpeace.com/products/hd-hearing-protection