The product is gold-plated xuping - also called medical gold. It is sold individually. Color change is minimized - durability is at a high level, but the personal acidity of the person who will use it should be suitable for using such products. There are skin acids that even melt gold and change the color of gold. It is a compression earring. You do not need to have a pierced ear to use it. It does not affect pool and sea water. It should be protected from chemicals. Since it is a hygiene group product, it is not suitable for exchange or return.