In this video I give a brief explanation of the HecksherOhlin theory and the Leontief paradox.
The HeckscherOhlin theory of trade predicts patterns of trade based on nations' relative factor endowments. In other words, the relative amount of labour, land and capital available in the country. A county is predicted to export products that a produced using factors that are relatively more abundance. This is because abundant factors are likely to be relatively cheaper.

The Leontief paradox show that this might not always be the case.