A microcentrifuge tube, also known as a microtube or a microfuge tube, is a small tube typically used in laboratory experiments for the purpose of holding, separating and storing small volumes of liquid or solid samples. Microcentrifuge tubes are usually made of plastic or glass and can range in size from 0.2 mL to 2 mL. They are designed to be used in microcentrifuges, which are instruments that spin the microtubes at high speeds to separate substances by density. Microcentrifuge tubes are an essential tool for many laboratory experiments, and are used in a variety of scientific fields including molecular biology, biochemistry, and genetics.