The Combat Arms Earplugs Version 2 (CAEv2) was manufactured by Aearo Technologies, Inc. prior to being taken over by 3M in 2008. The dual-ended 3M CAEv2 combat earplugs served as a standard form of military hearing protection in foreign conflicts for more than a decade, from 2002 to 2016. The 3M military earplugs are made of green and yellow with a double-ended design. The green end is inserted in order to block all sound, and insertion of the yellow end reduces the sound of gunfire and explosives but still allowed the service personnel to be part of a conversation. According to several lawsuits filed, the defective military earplugs cause two primary medical issues, tinnitus and hearing loss, mostly among veterans in the Navy and Air Force. The product was discontinued in 2015.