Sterilizer is a container, generally in a shape of a tube, in which ultraviolet (UV) is contained with fluorescent lamp. This lamp releases light at around 254 nm. The lamp is made up of quartz glass to avert the ultraviolet being absorbed, which is not done if ordinary glass were used. The lamp is covered of its own to protect it from water, and then there is an external container. The water is passed through the inner and external containers by a power head or pump.

Sterilizer is used to make free from living bacteria or other microorganisms. It eliminates the reproductive organs to dispose of the ability to produce offspring in microorganisms. Sterilize is to make something germ free and make it infertile. Ultraviolet sterilizer is a tool that sterilizes water by passing it through glass tube with the help of ultraviolet rays.

Ultraviolet sterilizers protect in removing parasites, bacteria and algae spores generally from aquarium. However, they can also disinfect some favorable organisms from reef tanks.

Thus, sterilizer is initial decontamination and cleaning of the instruments. It is useful for assembling and inspection of the instruments. In hospital no instruments can be used since they would not sterile when required.