The unique one size 3M E-A-R Tracer ear plug fits most ear canals comfortably and provides high levels of attenuation.Tracers offer the same features as UltraFit earplugs whilst in addition being metal detectable. They also incorporate an easy to see blue vinyl cord, the only colour classified as non-food colour. This makes them ideal for the food manufacturing industry , Comes with storage case. SNR = 29dB, EN 352-2:2020