The 3M Versaflo M-930 Visor lock kit is an accessory to 3M Versaflo M-400 Series Helmets. The lock mechanically attaches the visor frame to the jaw of M-400 series helmets with the intent to prevent lifting of the visor if needed or preferred by users. The lock is sold as a retrofit kit with 5 locks, and can be installed on new or existing helmets. Helmet purchased separately.The 3M Versaflo M-930 Visor lock kit is an accessory to 3M Versaflo M-400 Series Helmets. Some users might have a preference for a fixed visor without the option to raise. In those instances, the user can install the visor lock, which mechanically attaches the visor frame to the jaw of M-400 series helmets with the intent to prevent lifting of the visor. The lock is sold as a retrofit kit, and can be installed on new or existing helmets. The M-930 visor lock kit is sold in packages of 5. Helmet purchased separately. The lock kit comes with 5 visor locks, 10 screws, and 1 drill guide. Some installation required.