You can check the RN. Occasionally it leads back to their manufacturer, though more often than not it'll just give you the contact details for the clothing label. If you're looking at smaller manufacturers who just use premade blanks (like a typical internet retailer) then you're a lot more likely to get a positive hit.
With regards to the actual manufacturer that produced a certain garment, it is too difficult to determine since many companies use multiple facilities and vendors in their supply chain (an RN # will not always reveal this info).
However, you can easily achieve the same quality of any garment you are interested in replicating. It is not a complicated process, but working with a qualified sourcing and production company will make it easier and more cost effective to produce.
Is there a way of finding out which manufacturer certain companies use??
Do you have a particular garment (t-shirt, polo shirt...) and/or companies that you want to find out? Are you talking about the manufacturer use for example by Hanes, Fruit of the Loom and so on? As far as I know most of this garment are done overseas.
yeah, At certain degree, the wholesaler remove all the information you can contact with the manufacturer. And most most of the garments and apparels are made in China. Our factory in China is offering many OEM service for the companies in the US. The price is really cheap.
who is their manufacturer?? 
