SparkPlugs® Earplugs are made of extra-soft, extra light foam. Their tapered shape fits easily in the ear canal and seals gently and snugly without pressure. SparkPlugs® Uncorded earplug offer a high NRR 33, making them suitable for most noisy environments. So, while they look like fun, they provide serious protection. Highest independently tested NRR. Extra-soft, low-pressure foam for comfort and fit. Tapered shape for easy insertion and removal. Shaped to fit even very small ear canals. Non-irritating smooth surface.