Avantages
There are not many pros in the company. If you want to work for them for free, you can join the company and work as long as you want(6 months, 1 year, so on...), they won't ask you any questions until and unless you ask them to pay you for your work.
Inconvénients
Initially, they would ask you to work for free stating that they are testing you and would convince you to work free for 1-3 months or more. They would try to convince you to train first and ask money in return. Then if you get selected(you will if you agree to work for free) they will demand money about 4000 with 1-year bond and original document so that you cannot leave until they want you to. Their Manager/HR(One person handles all stuff) is the one to be careful of and he cannot talk in a professional way and uses bad words.