A cell spreader or plate spreader is a manual tool used in biology and related fields to gently spread cells and bacteria on a culture plate, such as a Petri dish. Cell spreaders can be made of glass, plastic or metal and come in a variety of shapes. Each of these materials has distinct advantages and disadvantages. Glass, for example, can easily be sterilized for repeated use. Glass, on the other hand, is fairly easy to break. Broken glass, in turn, represents a potential danger to researchers in the laboratory. Plastic, on the other hand, does not need to be sterilized because these spreaders are delivered ready for use. There are 3 main shapes: the L-shape, the T-shape and the triangular shape. It is essential to have a smooth spreader to prevent the medium (such as agar) from being nicked or cut. Destruction of the physical integrity of the culture medium can seriously compromise any attempt to grow a good cell or bacterial culture.