The waterfall product development process is a linear approach to development where each phase must be completed before moving on to the next. This process is often used in industries where there is a need for strict regulation and compliance, such as in the medical or aerospace industries. The main advantage of this process is that it allows for clear milestones and deliverables. However, the disadvantage is that it can be inflexible and does not allow for much iteration or revision. In addition, if any problems occur in earlier stages, they can often ripple down and cause delays in the later stages. As a result, the waterfall product development process is best suited for projects with well-defined requirements and little room for change.