InstallationSelf-Installation Instructions for Helmets and Speakers Determine if ear noise reduction muffs will fit in your helmet. Helmet Speaker Installation HJC 2012 Model CL Modular Helmet Installation Open Face FG-JET Snowmobile Helmet Installation Shoei Neotec Modular Helmet Installation NEXX Dual Sport Helmet Tools Needed to Modify All Helmets Download PDFsHelmet Speaker InstallationHJC 2012 Model CL Modular Helmet InstallationOpen Face FG-JET Snowmobile Helmet InstallationShoei Neotec Modular Helmet InstallationNEXX Dual Sport HelmetTools Needed to Modify All Helmets