Original Equipment Manufacture (OEM) is a contract production of already existing things but under your own trade mark. In fact, it means the copying of already existing products in China.
A plus is that this type of production is quick and cost-effective. That being said, your product is not unique (though this type of production is often oriented at a specific country). However, if your product is not oriented at a specific market, it is highly likely not adjusted to it. For instance, the size, design and other things may not fit the customers in the import country.