blocks stinks [SEP] love these i bought them for work but have ended up using that at home more they work really good as long as you remember to breathe through your nose and not your mouth i have reused the same pair a few times with no issue i have recommended these to lots of nurses cnas at my work and i am so glad i found them the only hiccup was shipping it gave me a delivery date very far out they showed up pretty quick compared to the estimated date but they still show in my amazon that they haven t arrived i am glad they came quicker