Businesses in the optical instruments category supply equipment that uses lenses, mirrors or other optical components to observe, measure or record light and images. Products may include binoculars, telescopes, microscopes, magnifiers, spotting scopes and optical accessories such as eyepieces, filters, mounts and tripods. Some suppliers focus on particular users, including schools, laboratories, photographers, surveyors, astronomers or people who need instruments for outdoor activities. Depending on their specialism, businesses may also provide advice on selecting suitable equipment, demonstrations, installation and after-sales support. Services can include cleaning, adjustment, repair or servicing of instruments, and supply of replacement parts. Specialist suppliers may offer measuring or inspection equipment, such as optical levels, rangefinders, lenses and imaging systems.