This document describes the features and applications of the R 27, R 28, and R 29 temperature controllers. They are suitable for household appliances, electronics, and mechanical engineering. These controllers have various connection options, small tolerances and hysteresis, and trigger temperatures ranging from 0°C to 260°C. Additionally, they can handle up to 100,000 switching cycles. The technical specifications and certifications of each model are also provided in the document.