3M™ E-A-Rfit™ Dual-Ear 1/4-20 to 5/8-27 Speaker Stand Adapter is designed to attach the 3M™ E-A-Rfit™ Enclosure Assembly Speaker to the speaker stand. These accessories work with the 3M™ E-A-Rfit™ Dual-Ear Validation System to help employers determine whether workers are getting adequate hearing protection.