The Peltor Tactical Sport has an audio input jack for connecting an external radio, and a level dependent function that amplifies weak sounds and attenuates loud ones. The external communication and level dependent functions are independent of each other, which ensures extra reliability and better safety. Inner attenuation cushion and padded ear cup cushion provide a comfortable fit. Interchangeable outer cup shells designed with standard black cups and one extra set of orange cups. The earmuffs conveniently fold up for storage.FEATURESInternal digital electronics for superior ambient sound reproduction Noise Reduction Rating (NRR): 20dB Folding headband for convenient storage Interchangeable outer cup shell design with standard black cups and one extra set of orange cups Volume control and on/off switch Audio input jack for connecting an external radio Operates with 2 AAA batteries Approximately 600 hours of usage per battery set