An open source ventilator is a disaster-situation ventilator made using a freely licensed (open-source) design, and ideally, freely available components and parts. Designs, components, and parts may be anywhere from completely reverse-engineered or completely new creations, components may be adaptations of various inexpensive existing products, and special hard-to-find and/or expensive parts may be 3D-printed instead of purchased. As of early 2020, the levels of documentation and testing of open source ventilators was well below scientific and medical-grade standards.