Noise Reduction Rating: The Max Protec 26 from Walker’s is a passive earmuff with a Noise Reduction Rating (NRR) of 26. Headband: It features a super strong polymer vented adjustable headband. Ear Pads: This earmuff features soft PVC ear pads. Sculpted Cups: The sculpted cups do not interfere with helmets or hard hats. Dielectric: This earmuff is dielectric i.e. it does not conduct electricity.