They are tariff and quota free, allowing manufactured goods to be exported at no cost.
Unions are usually banned, so workers cannot neither strike nor complain.
Infrastructure such as port facilities, roads, power and water connections are provided by the government, providing a subsidy for investors and lowering their cost.
All profits made can be sent to the company HQ overseas.
Taxes are usually very low, and often there is a tax-free period of up to 10 years, after a business invests.
Environmental regulations are usually limited.