Extech DO600 Information The Extech DO600 is a waterproof dissolved oxygen meter that is designed for use in a variety of applications, including aquaculture, environmental monitoring, and industrial water quality testing. The meter features a compact and lightweight design that makes it easy to carry and use in the field. It also has a number of advanced features, such as adjustable altitude and salinity compensation, an analog bar graph, and a data hold function. Introduction The Extech DO600 is a handheld dissolved oxygen meter that measures the amount of dissolved oxygen (DO) in water. DO is an important measure of water quality, as it is essential for the survival of aquatic life. The DO600 can be used to measure DO in a variety of water bodies, including lakes, rivers, streams, and aquaculture tanks.