Well, K is simply the ratio of the concentration of products and the concentration of reactants at equilibrium when the Navy equilibrium has been established. And what K does is it tells us how far the reaction proceeded at equilibrium. In other words, we can have three situations. K can either be greater than one and if K is greater than one, that means at equilibrium we have more products than reactants. And that means our reaction is a product favored, it's spontaneous going this way. Now, if K equals one, that means at equilibrium our concentration of products is the same as the concentration of reactants.