The Pro Tac Plus Gold has a contoured cup for lower weight for long term use. Maximum concealment. All firearms can be used with this cup profile comfortably. The NRR is 26. Provides excellent noise attenuation. Llightweight and concealable cups. These Pro Tac Plus Gold units have the fastest “attack time “in the industry at 1.5 milliseconds. Excluisve DLSC technology which allows the user to hear all commands-whether indoors or outdoors-clearly despite continuous gunfire to ensure maximum safety. These Gold Series units are extremely comfortable with Pro Form Leather ear cushions that don't crack or sweat. Contain an 8 bit micro processor that ensures the unit is running right every time.