The plugs he had didn't attenuate 90dB, their filter started at 90dB input. I don't know the actual attenuation.
I quess they could be something like the Noise Breakers at this link http://earplugstore.stores.yahoo.net/honobr.html
but these are only rated at 19db NR, pretty low for shooting. Or perhaps the Sonic Blast at this site http://www.perfect-seal.com/earplugs.html
or the Sonic Valve at this site http://earplugstore.stores.yahoo.net...ear-plugs.html
but once again only rated for 19dB NR.