Pro custom oil is a blend and one of the main components is Tung oil. These blends are known as oil modified polymers and they typically contain urethane varnish, oil (usually tung) and dryers like Japan dryer.

Click the link and then click the link to technical specs:

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=273505

Lot's of people are using tung oil and dont know it cause they are buying a prepared blend and don't have any knowledge of what is in it. These blends are easier to use than straight tung and IMO leave a more durable finish.

I make my own blending the components in small batches as I need them.

Jeff

Jeff