Ear Tips are used in earphones only and it is worn over the earphone stem aka nozzle which helps our ears to get a secure and tight fit. Different kind of earphones offers different fitment, isolation and sound too. The sound signature sometimes changes drastically from different ear tips to ear tips and one should experiment with different ear tips to get the desired sound they want. The material of the ear tips these days comes in a wide variety like silicone, foam, memory foam and the combination of silicone and memory foam known as hybrid ear tips.
Earphones Ear Tips come in 3 sizes:
If your ear canals are very small so you should try the small ones, if your ear canals are in average size so medium size will fit, if your ear canals are large in size so large size will fit.
Please note, different manufacturers' ear tips may sound different on the same earphones you are using so always experiment with ear tips to get the desired sound character.
Please note, different manufacturers' ear tip sizes are not the same across the many manufacturers.
So every earphone eartips are different from each other as some ear tips come in narrow-bore sizes and some come in normal bore sizes and some come in wide-bore sizes.
Narrow-bore ear tips usually accentuate the bass whereas wide-bore ear tips usually accentuate the balance across the entire frequency spectrum i.e., from bass to treble.
Memory Foam earphone eartips are usually get used for the reduction in treble area and for comfort.