Therefore, the order penetration point entails decoupling points, each with its decoupling inventory. In general, decoupling points in the product structure are items downstream from the OPP with at least one direct component upstream from the OPP. In the example of Figure 1.3.1.3, item A is the only decoupling point. It is downstream from the OPP, whereas its direct components C, D, and E are upstream from the OPP.