The Pro Tac SC Gold has a chop cut cup for lower weight, and easy shouldering of long guns. Maximum concealment. All firearms can be used with this cup profile comfortably. The NRR is 25. Provides excellent noise attenuation. Lightweight. Pro Tac SC Gold units have the fastest “attack time “in the industry - 1.5 milliseconds. Excluisve DLSC technology which allows the user to hear all range commands-indoors or outdoors -clearly despite continuous gunfire. These Gold Series units are extremely comfortable with Pro Form Leather ear cushions that don’t crack or sweat. Contains an 8 bit micro processor that ensures the unit is running right every time. Automatic shut-off. Low battery indicator.