3M™ E-A-R™ Earmuffs, Hearing Conservation 330-3002 Model 3000. Features durable, lightweight construction of non-conductive, dielectric plastic that can be worn over-the-head, behind-the-neck or under-the-chin. This earmuff combines excellent attenuation with comfortable durability. Provides a protective seal without excess pressure while the pivoting ear-cup connections help maintain the seal and proper alignment. These lightweight earmuffs may be worn over-the-head, behind-the-head, or under-the-chin. Large ear-cup openings and soft, foam-filled cushions offer a snug, comfortable fit. Durable, lightweight construction of non-conductive, dielectric plastic. Noise Reduction Rating* NRR 25 dB (CSA class A) when the band is worn over-the-head. NRR 26 dB (CSA Class AL) when the band is worn under-the-chin. NRR 26 dB (CSA Class AL) when band is worn behind-the-head.