A set of earmuffs has an NRR of 30 dBA, and a set of plugs has an NRR of 20dBA. Workers in a car factory are exposed to 110 dBA for 8hrs. Before advising management on whether to purchase muffs or plugs, you do a small trial on the factory floor. Workers wearing the muffs take them off for half an hour each day while working due to discomfort whereas plug wearers soon forget they are wearing them and keep them in all day. Which device will give the best ear protection in practice?