The Walker's Digital Razor Electronic Earmuffs are designed with a new ergonomic head band design for comfort and support. They feature a powerful NRR rating of 23dB, as well as active dynamic sound suppression for safety at the range. To ensure the preservation of the two AAA batteries; the Digital Razor features an auto shut off at 2, 4, and 6 hour marks. The Digital Razor is a high performing set of earmuffs which deliver amazingly fast reaction times which ensure optimum protection at the range. Audio Input Jack.