3M Classic Disposable Earplugs 29db CL4 200PK 312 1201 Two Tone 3M™ Bayonet Connection System ensures HEC674 3M™ Bayonet Connection System ensures precise and secure lockingLow profile and well balanced twin filter designSuitable for use with 3M™ 6000 7500 Series Half Face Respirators and 3M™ 6000 7000 Series Full Face Respirators while the quick detach wall mount ensures easy portability in emergencies enabling them to remain fitted particularly in warmer conditions as they are less likely to swell through moisture absorption 3M™ E A R™ Classic™ uncorded earplugs set the standard in hearing protection as the world's first foam earplugs