Caldwell E-Max Pro Ear Muffs Bluetooth Bluetooth connection;Allows communication between multiple users;Ambidextrous boom mic;Works with other Bluetooth hearing protection via Comm Link (sold seprately)table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; } Item Category Code: 3700 Product Group Code: 3700B Inactive: Yes Prop65 Applies: Yes Prop65 Cancer Harm: Yes Prop65 Chemical: Chromium (hexavalent compounds)