There are several instruments or systems on the market that are less sophisticated than those discussed in previous sections. In general, these instruments can perform only parts of a microbiological analysis and cannot make decisions or interpret the data independently. Their chief usefulness is in performing a manual chore automatically. These instruments include microdilutors, which are primarily used for MIC determinations; the Cathra International Repliscan® which mechanizes portions of the traditional methods for identification and antibiotic susceptibility; and gas chromatographs, that are mainly used in the clinical laboratory for identification of anaerobes or bacteria that are difficult to identify by traditional methods.