MSA customer service number for Sordin Muffs: tel:1-800-672-2222
If you are in the US, and you have muffs purchased from someplace other than an MSA authorized dealer, you may have service issues. There are unauthorized dealers that are distributing MSA/Sordin muffs in the US. They are bringing the muffs in from Europe and switching out some of the electronics. MSA North America will not service these units and they will have to be returned to the point of purchase. Buyer be ware.