Soundmagic is actually a pretty old Chinese audio brand that started making inexpensive In Ear Monitor (IEM) earphones many years ago when people hardly knew any Chinese company making earphones. Those days earphones were almost exclusively made by American, European or Japanese companies like Westone, Audio Technica, Shure, Earsonics, JVC etc.
In those days, earphone development was slow and you really needed to spend a good bit of $$$ to get some really good sounding earphones.
That all changed once Chinese manufacturers broke into the earphone market. First they were trying to make low-cost copies of other manufacturers products. However, as time went on Chinese manufacturers started doing real innovation by developing their own drivers and the advent of different technology like tunable drivers, dual dynamic earphones etc.
Soundmagic is one of those early innovative brands that came out with one of the first Balanced Armature driver earphone for under $50 at a time when people had to pay over $100 to be able to afford a Balanced Armature driver earphone.
Nowadays you get Chinese earphone manufacturers at all ends of the earphone market from budget to very high-end custom IEMs that cost > $1000.
Soundmagic, however, decided to play to its strengths – Make earphones that sound good at a price point that almost anyone can afford. It was manufacturers like Soundmagic that forced other manufacturers to innovate and greatly improve their lineup to bring in better sounding earphones at much lower price points.
In fact, I am sure than merely 10 years ago, this $15 Soundmagic ES18S would probably sound as impressive as a $80 earphone from that time!
So coming back to the Soundmagic ES18S, this is the microphone version of the cheaper ES18 earphone.