I had a pair of silicone earplugs made a number of years back to wear while riding the motorcycle. I've used them since in the shop for hearing protection, they work great. What I didn't know when I bought them, is that because the silicone is stiffer than the skin in your ears, if the skin/muscles around your ears move (yawn, chew, swallow, flex your ears, whatever) the seal can be broken momentarily, resulting in momentary lack of protection. The foam earplugs seem to conform fast enough to keep up if you are doing any of these things. Just my experience, ymmv, etc. I still love the silicone plugs for the shop, much more comfortable than over-ear cups.