please i want to know the what kind of visa is this.

Its a work visa

It's a working visa valid for 5 years, but whenever you exit you need to get an exit re-entry visa. You cannot come in and out as you wish you need to get a re-entry visa every time you wish to exit if you intend to come back again! otherwise, without exit re-entry visa, you cannot enter again even it is still valid for 5 years as it is only one entry visa. :)

eh? and who has issued this visa to you? why you cannot ask your employer? Or you are implying that you don't trust your employer?