3M Combat Arms Earplug
The Combat Arms Earplugs are small, dual-ended earplugs designed for servicemembers who need both options for hearing attenuation. The “closed” option functions as a traditional earplug to block out sounds completely, while the “open” option dampens the sound of explosions on the battlefield, allowing the wearer to still communicate and hear commands.
3M, the maker of Dual-Ended Combat Arms Earplugs, Version 2, supplied the U.S. military with 2.2 million of these earplugs between 2003 and 2015 to protect military personnel from damaging noise related to combat. In practice, however, the earplugs were too short which made them loose, causing hearing loss and, for some users, tinnitus.