Howard Leight MAX Uncorded Foam Ear Plugs - 200/Box MAX-1 Pre-Shaped Uncorded NRR 33 Disposable Earplugs. Workers who need to block out loud noise demand the best protection and comfort available in an earplug. That's where MAX comes in. The world's most popular polyurethane foam earplug, MAX offers superior noise-blocking performance in a single-use disposable earplug. MAX's enhanced contoured shape is easier to insert and resists backing out of the ear canal, while its softer foam delivers superior long-wearing comfort delivering solid performance that your workers can depend on