Tested to ANSI S3.19-1974 standards, this dielectric earplug has an NRR of 27. Its tapered design and sturdy stem allow for easy insertion and removal and a comfortable fit in the ear canal. Made from soft thermoplastic rubber (TPR) the FP42 and 43 are non-irritating to the skin. They are available uncorded (100 Box) and corded (100 Box) and in case quantities.