Made of polypropylene, they can be use in very low temperature or with organic solvents such as chloroform. They come in many different sizes, generally ranging from 250ul to 2.0ml. The most common size is 1.5ml. Disinfection is possible and is commonly performed in works related to DNA or microbes, where purity of the sample is of utmost importance. Due to their low cost and the difficulty in cleaning the plastic surface, they are usually discarded after each use