How many hours does the refrigeration worker work a month? What's the average salary?

The refrigerator works in three shifts, working eight hours a day and taking four days off a month.

There are also two shifts, working 12 hours a day, taking two days off in the last two days and one month off 14~ 15 days.

The salary is 4000 ~ 5000+ in coastal areas and 3000 ~ 3500 in inland areas.