The earplugs involved in this massive litigation are 3M dual-ended Combat Arms earplugs (CAEv2). These earplugs were sold to the U.S. military under a massive contract with the U.S. Department of Defense. After thousands of the earplugs had been issued to servicemembers, it became known that they were defective. 3M admitted that they knew the earplugs were defective but did nothing to mitigate the risk to active duty soldiers. 3M never recalled the defective earplugs but did stop selling them in 2015.