Temperature-controlled water baths and circulators are used in a variety of academic, clinical, and industrial settings. Instrument categories includes, water baths, circulating baths, and external circulators. Basic features of operation include temperature control elements, circulation pumps for precise temperature uniformity, and coupling with complex analytical equipment, in the case external units. Key considerations include: accuracy of temperature control, precision range of temperature uniformity, cooling/heating rate and range, and maintenance. Advanced features such as touchscreen operation and onboard methods may also be available.