That's how you can write the English plural s in Korean.
Remember that you can't write ㅈ (or any other consonant) by itself, it needs to be followed by a vowel. So, the neutral ㅡ is often used in such cases.
Another example with a different consonant, Starckbucks: 스타 벅스
I don't know the rule which decides when it should be 스 and when it should be 즈 for a final s.