Shure In-Ear Earphones reviewed here.
Seen those things stuck in performers ears at concerts? Those are “monitoring devices” that, apparently, block out a lot of sound except what’s coming through the earphone (they claim 10-20dB attenuation). ExtremeTech explains about ’em and reviews 2 of Shure’s. Go to Shure and look for E1C and the E2C.