Cause ear plugs do not itchy ears

I have quite sensitive ears to itch immediately start when the stud earrings are not really 100% silver (apparently, in many ear plugs at the Lötnäten or plugs, which then pass through the earlobe or mixed another metal with the silver, because silver is very soft is). These ear plugs I finally found what I can be day and night in there without getting red, itchy earlobes. I think the size is just right (as indicated in the product description). Bigger they should not be.