3M™ E-A-R™ Classic™ Small Probed Test Plug are a modified version of the disposable foam 3M Classic Small Earplugs you know and use, specially designed to be used with the 3M™ E-A-Rfit™ Dual-Ear Validation System Our earplugs are the same model sold as standard, but engineered specifically for use with 3M™ E-A-Rfit™ Dual-Ear Validation System. The complete system issues a pass or fail rating based on the employee's personal attenuation rating (PAR) when wearing 3M earplugs. These probed earplugs allow employers to determine the level of protection the specific model of earplug is providing. Workers can use the probed versions of the existing model of earplugs they’re using in the workplace and assess their fit and compliance. Using the probed test ear plugs the 3M™ E-A-Rfit™ Dual-Ear Validation System measures the effectiveness of the hearing protection from inside the employees ear, providing accurate quantitative results. These probed test plugs are for use with the system only and are not suitable for use as hearing protection. There are 50 pairs in each box.