Hearos F4 Series 7421 Reusable Ear Plugs (NRR 27)

Excellent Product! I use them as earphone tips, not as plugs - see below. As another reviewer mentioned, they are partly hollow down the middle of the shaft. I removed the white plug from the outer end, unfolded a paper clip and shoved the inch or so long wire in to test how deep the hollow center is - and it goes to within about 1/16 inch from the inner most domed small end. I then removed the paper clip. I wanted some 3 flange tips for my Etymotic and Westone earphones, so, I cut off the end smallest blue dome (this reveals the center shaft hole), and then cut away one section of the outer shaft, leaving enough shaft to grab them. They fit very tight on both earphones. I did not cut the 1/8 inch section off the outer shaft for the Etymotics because I needed more to grab onto to get them out. The center shaft hole is small but it does not affect the sound quality - perhaps a tiny bit of attenuation only. The 2 middle shaft rings and big outer dome "ring" make a soft, comfortable 3-ring seal. The outer dome is big and squeezes and seals the entrance to my tall oval ear canals, and the inner 2 rings are much smaller to seal my rapidly smaller inner canal area. They are short, so, they don't push on the sensitive bend-2 area. (The photos make the product look way too long. The parts that count are not too long as above).

I wear ear plugs for motorcycle riding and lawn mowing to reduce wind or engine noise respectively. My go-to plug is the Howard Leight Smart Fit but I am always looking for something with a better NRR. The Hearos F4 did a nice job of drowning out the lawnmower but I found them too hard and inflexible for extended wearing such as a long bike trip. They're good ear plugs, they're just not comfortable under a helmet.

Work good unless the loud sound happens to be directly in line with your ear. Thye have a hole down the center. I shoved a wooden match stick in all the way until I hit bottom and broke off the extra. Now they work great. The rigidness the wood goves them makes them easier to use too. I like them now eanough to not be lookinbg for something better. Now I'm working with pink noise so I don't need them at all. - R